gns science report 2008 2012-018.pdf · miller, c.a.; jolly, a.d. 2012. results of consultation...

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BIBLIOGRAPHIC REFERENCE Miller, C.A.; Jolly, A.D. 2012. Results of consultation with the New Zealand volcanology research community for future GeoNet funding directions, GNS Science Report 2012/18 63 p.

C.A. Miller, GNS Science, Private Bag 2000, Taupo A.D. Jolly, GNS Science, Private Bag 2000, Taupo © Institute of Geological and Nuclear Sciences Limited, 2012 ISSN 1177-2425 ISBN 978-1-972192-00-9

GNS Science Report 2012/18 i

CONTENTS ABSTRACT .......................................................................................................................... III KEYWORDS ......................................................................................................................... III 1.0 INTRODUCTION ........................................................................................................ 1

2.0 RESULTS OF SUBMISSIONS AND SUBSEQUENT MEETINGS .............................. 2

2.1 Seismology .................................................................................................... 2 2.1.1 Aims ................................................................................................... 2 2.1.2 Overview of Submissions .................................................................... 2 2.1.3 Hardware Requirements ..................................................................... 4 2.1.4 Processing and Analysis Methods ...................................................... 4 2.1.5 Summary ............................................................................................ 4

2.2 Infrasound ...................................................................................................... 4 2.3 Geodesy ......................................................................................................... 4

2.3.1 Aims ................................................................................................... 4 2.3.2 Overview of Submissions .................................................................... 5 2.3.3 Hardware Requirements ..................................................................... 6 2.3.4 Processing And Analysis Methods ...................................................... 6 2.3.5 Summary ............................................................................................ 7

2.4 General Geophysics ....................................................................................... 7 2.5 Geochemistry and Hydrogeology ................................................................... 7

2.5.1 Degassing........................................................................................... 7 2.5.1.1 Aims .................................................................................... 7 2.5.1.2 Overview of Submissions .................................................... 8 2.5.1.3 Hardware Requirements ...................................................... 8

2.5.1.3.1 Field Sensors ......................................................................... 9 2.5.1.3.2 Lab Equipment. ...................................................................... 9

2.5.1.4 Summary ............................................................................. 9 2.5.2 Crater Lake Monitoring ....................................................................... 9

2.5.2.1 Aims .................................................................................... 9 2.5.2.2 Overview of Submissions ...................................................10 2.5.2.3 Hardware requirements ......................................................10

2.5.3 Hydrogeology ....................................................................................11 2.5.3.1 Aims ...................................................................................11 2.5.3.2 Overview of Submissions ...................................................11

2.6 Physical Volcanology ....................................................................................11 2.6.1 Ash ....................................................................................................12

2.6.1.1 Aims ...................................................................................12 2.6.1.2 Overview of submissions ....................................................12

2.6.2 Plume Remote Sensing .....................................................................13 2.6.2.1 Aims ...................................................................................13 2.6.2.2 Overview of Submissions ...................................................13 2.6.2.3 Hardware Requirements .....................................................14 2.6.2.4 Processing / analysis methods ...........................................15 2.6.2.5 Summary ............................................................................15

2.6.3 Lahar .................................................................................................15 2.6.3.1 Aims ...................................................................................15 2.6.3.2 Overview of submissions ....................................................15 2.6.3.3 Hardware requirements ......................................................16

2.6.4 Hazard Forecasting ...........................................................................16 2.6.4.1 Aims ...................................................................................16 2.6.4.2 Summary of submissions ...................................................16

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3.0 CONCLUDING REMARKS ....................................................................................... 17

4.0 ACKNOWLEDGEMENTS......................................................................................... 17

5.0 REFERENCES ......................................................................................................... 17

APPENDICES APPENDIX 1 – List of researchers who were sent questionaires ........................................................................... 21 APPENDIX 2 – Individual submission responses ................................................................................................... 23

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ABSTRACT

As part of a process to develop a long term work-plan for future GeoNet volcano monitoring, the New Zealand volcano research community was asked to comment on their specific area of research and how it contributes to volcano monitoring and hazard assessment. Researchers were asked to comment on improvements that could be made to the GeoNet monitoring programme to provide more comprehensive products of relevance to their work. To ensure consistency across responses, a 6 point questionnaire was sent to researchers in GNS Science and New Zealand universities. Once completed questionnaires were received and compiled, a series of meetings on each scientific discipline (geophysics, geochemistry and physical volcanology) were held with researchers to discuss their responses. From the written responses and follow up meetings, a series of high level themes have been developed for each discipline. These themes represent common topics in submissions which could be developed further into specific work items. Additionally any specific hardware or data processing and analysis requirements are listed.

In the geophysics discipline, it was generally found that the current networks are deemed fit-for-purpose, although there is scope for some improvement in network coverage of White Island and Taranaki. The main focus of both geodesy and seismology should be to apply advanced processing methods to derive applied data products for routine use. Geochemistry responses were focussed on acquiring higher data rate measurements across a wider suite of analytes. Physical volcanology submissions considered that there was a need for greater interagency cooperation during times of eruption to successfully capture and disseminate information about ash distribution on the ground and in the air.

This study together with the previous NZVEWS study on threat levels of New Zealand volcanoes (Miller 2011) will be used to draft a future GeoNet volcano monitoring strategy. This draft strategy will be presented to the next GeoNet international review for comment from the panel and to guide discussions on future recommendations.

KEYWORDS

Volcanology, Geophysics, Geochemistry, GeoNet, New Zealand, Consultation, Seismology, Geodesy, Crater Lake, Volcanic Ash.

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GNS Science Report 2012/18 1

1.0 INTRODUCTION

The first GeoNet volcanology work plan, developed in 2001, is now largely complete. Currently there is no long term plan to shape the future direction for development of the GeoNet volcanology programme. Recognising this, work has begun to formulate such a plan. This work has been undertaken in two parts. Part one consisted of an “NVEWS” style assessment (Ewert 2005) of New Zealand’s volcanoes with respect to their threat potential (called NZVEWS). This work outlined gaps in current monitoring instrumentation (including seismology, geodesy and geochemistry at each volcano, (Miller 2011).

The second part was to seek feedback from the New Zealand volcano research community on what they see as possible future volcano monitoring requirements that could come under the GeoNet umbrella. Information was sought which would enable GeoNet to better fulfil its monitoring responsibilities and therefore inform real time hazard assessment and mitigation at New Zealand’s volcanoes.

This process was initiated by circulating a brief questionnaire to a wide spectrum of researchers involved with New Zealand volcanoes asking them to comment on their specific area of research and how it contributes to volcano monitoring and hazard assessment. They were asked:

• What kind of data is required for their area of research?

• What results can be achieved with the collected data?

• What is the time frame for deriving those results?

• How can the results better inform monitoring for volcanic hazards?

• How can data collection be improved?

• What are possible future developments in their field?

Once submissions were collated, a series of meetings were held in 3 broad subgroups of 1) Seismology, geodesy and geophysics; 2) Geochemistry and groundwater; 3) Physical volcanology, including ash fall, lahar, hazard assessments and experimental volcanology. These meetings were designed to let the researchers speak to their topics and also address other submissions, and comment on any obvious gaps – i.e. where no submissions had been made. From the written submissions and subsequent meetings a series of high level objectives covering common themes were drawn together (Section 2). Individuals that were sent questionnaires are listed in Appendix 1 and submissions received are presented in Appendix 2.

Together with the researcher submissions and the NZVEWS study, a draft future GeoNet volcano monitoring strategy can be developed. This strategy will be presented at the next GeoNet international review for comment from the panel and to guide discussions on future recommendations.

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2.0 RESULTS OF SUBMISSIONS AND SUBSEQUENT MEETINGS

A universal theme across all disciplines is to ensure that GeoNet monitoring remains linked in to volcanology research programmes across New Zealand and overseas. It is recognised that volcanological research is funded through various sources (for example, Natural Hazards Research Platform, CRI core funding, Marsden, EQC contestable) and does not require further GeoNet input. This includes geochronology, stratigraphy, mapping, experimental work on eruptive processes, physical and numerical modelling, and volcanic impacts work. Regular dissemination of research results to the monitoring team, and vice versa is viewed as important so that monitoring data can be placed in its proper context; equally, conceptual and numerical models can be tested on real data. This interface between monitoring and research can be achieved through presentations at monitoring meetings, at scheduled volcano specific science forums (e.g. Central Plateau Volcanic Advisory Group or similar) or at national or international conferences.

The following sections summarise the written submissions and follow up discussion meetings. In each section a brief description of the overall aims of the discipline are given; these are followed by an overview of the submissions. To highlight the main points of each group of submissions, a series of high level themes are developed (often relating to commonalities in submissions) and are highlighted in text boxes. These themes are individually numbered. Any specific hardware or analysis/processing requirements are then listed. A brief summary is then given for each discipline.

2.1 Seismology

2.1.1 Aims

Volcano seismology is the most fundamental volcano monitoring discipline. Essentially, the aim is to use seismic waves to monitor subsurface changes that may reflect changing crustal structure or fluid migration caused by magmatic intrusion or geothermal activity. The basic requirement is to accurately locate earthquakes associated with volcanic activity and assign magnitudes. However with modern dense sensor networks more complex data analysis is possible (McNutt 2005) including: the ability to model long period (LP) (Hagerty et al. 2003, Jolly et al. 2012), very long period (VLP) (Jolly et al. 2010) and tremor waveforms (Hurst et al. 1993) to determine source characteristics through time; measurements of changes in shallow crust velocity structure (Mordret et al. 2010); changes in crustal anisotropy (Titzschkau et al. 2010), and changes in the stress state of the crust (Roman et al. 2008). Many of the above mentioned studies have been undertaken using data from the existing GeoNet New Zealand volcano seismic networks.

2.1.2 Overview of Submissions

Written submissions were received from the following people: Steve Sherburn, Tony Hurst, Martha Savage, Tim Stern, John Townend, Art Jolly, Bill Fry. A follow up meeting was attended by Craig Miller, Steve Sherburn, Art Jolly, Nico Fournier, Tony Hurst, Martha Savage, Bill Fry.

A variety of processing techniques are recommended but most of them have overlapping instrumentation and raw data requirements. Nearly all submissions focussed on advanced processing techniques; this is taken as a positive sign that the basic network configuration for data collection is suitable.

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From the written submissions and follow-up meetings the following high level themes were developed.

1) Locating Earthquakes for Volcano Seismology

Includes location of volcano-tectonic earthquakes (VTs), volcanic earthquakes, tremor, high precision locations of all earthquakes and analysing earthquake swarms in near real time. Knowing the location of seismic signals from volcanoes is important for determining their significance from a hazards perspective. Implementation of existing methods to do this with low latency in a routine manner is seen as important so that changes in signal locations and characteristics can be interpreted in a timely way.

2) Volcano Seismology Modules for SeisComP3

Includes implementing an “S” picker, automatic derivation of amplitudes, long period (LP) and very long period (VLP) detectors. Automated production of these data by SeisComP3 will significantly streamline more advanced processing which uses them as input.

3) Broadband vs Short Period Sensor Distribution

Different techniques require different types of sensor. Uniform sensor distribution is good but there needs to be consideration of the optimum distribution of Broadband (BB) and Short Period (SP) for modern analytical techniques. The current station distribution is generally good but extra stations located over repeating earthquake source regions would be useful (e.g. Waiouru and National Park swarms).

Some of the methods that can be routinely used if higher level data processing is provided include:

• Stress mapping using focal mechanisms.

• Local earthquake tomography (LET) to provide more accurate velocity models which in turn provide better earthquake locations.

• Locating volcanic earthquakes/tremor to understand how they relate to the volcano/hydrothermal system.

• Cataloguing tremor and LP earthquake spectra changes with time as a proxy for changing source or path conditions.

• Modelling the causes of LP and VLP earthquakes to determine their significance from a hazard monitoring perspective.

• Stress mapping using focal mechanisms and shear wave splitting (SWS) to detect changes which might be associated with magmatic intrusion. These could be done as part of routine analysis.

• Measuring crustal velocity changes on daily time scales to detect intrusion of fluids. Such information may be used to infer if processes are magmatic or non-magmatic in nature.

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2.1.3 Hardware Requirements

No wholesale changes to network configuration are advocated with points being noted below.

• Extra stations to fill coverage gaps (for better LET coverage).

• Extra stations directly over earthquake swarm areas (for example, Turangi, Waiouru, National Park, Matata) for studies using these earthquakes as input data.

• Source modelling studies need BB stations (LP and VLP), although for Shear Wave Splitting either BB or SP instruments are adequate. Mantle structure studies prefer BB so potentially some BB coverage over a wider area (not just on cones) would be useful. A full review of distribution of sensor types needs to be undertaken.

• Use of borehole instruments in noisy areas.

• White Island requires additional seismic stations for network redundancy and to allow more advanced analysis techniques to be applied.

2.1.4 Processing and Analysis Methods

• Better phase and amplitude picks (with 1st motions) and including S phase picks.

• Moving to a “real-time” automated earthquake catalogue.

• Pre-calculation of Green’s Functions for target regions to allow for more rapid volcano source modelling.

• Pre-calculation of station transfer functions to allow for more rapid modelling.

2.1.5 Summary

Practically all respondents highlighted the need for more advanced analysis techniques of existing data as the main requirement. Some increase in station numbers may be needed in selected areas to improve the functioning of these techniques, and a detailed analysis of sensor type across volcanic areas should be undertaken. Use of boreholes to improve site quality is acknowledged.

2.2 Infrasound

Two submissions called for increased infrasound instrumentation. After discussions it was thought that it is best to focus on single station sensors at volcanoes likely to have explosions rather than invest in multi sensor arrays. New Zealand currently does not have a strong research capability in infrasound processing, analysis and modelling.

2.3 Geodesy

2.3.1 Aims

Volcano geodesy is a major volcano monitoring discipline and one that has seen rapid technological growth over the past 20 years with the advent of “space geodesy” taking over from classical terrestrial geodesy (Dzurisin 2007, Segall 2010). The use of powerful computers and new analytical models (Poland et al. 2006) have also greatly increased understanding of the processes behind the observations. Geodesy aims to measure

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deformation at the earth’s surface or in boreholes, that are caused by changes in the earth’s crust. These changes can be related to fault movement, fluid movement or the expansion and contraction of volumetric sources (magma bodies, dykes etc, for example, Bonanno et al. 2011, Chadwick et al. 2011). Using geodesy it is possible to model the location and properties of these sources and hence gain insights as to whether they are caused by hydrothermal, magmatic or tectonic unrest (Battaglia et al. 2009). Geodesy in the past decade has progressed from sparse campaign style measurements to rapid sampling (>1Hz) with real time transmission and processing of data. This has led to the real-time detection of transient deformation events providing the opportunity to better inform end users of natural hazards.

2.3.2 Overview of Submissions

Submissions were received from Fournier, Hurst and Miller.

Three common themes were identified from the written submissions and follow up meetings and are listed below.

4) Borehole strain

An update is required on the current state of play of PBO stations so that an assessment of the viability of borehole strain instrumentation for New Zealand can be undertaken. GNSS should not be the only method of determining strain. Tiltmeters should be included in future borehole strain stations.

5) Greater GNSS station coverage at White Island and Taranaki

6) Higher data rate continuous GNSS

GNSS solutions provided at seconds to minutes intervals, rather than hourly or daily averages as at present. At higher rates, GNSS instruments can be used as long period seismometers. The main challenge is to develop software to process, detect and model short period signals in near real time.

7) Campaign geophysical surveys

These are still important – for example, gravity, levelling, magnetics etc. Currently, GeoNet does not own gravity or magnetic instrumentation; this might be considered in the future.

As with the seismic networks, it was felt that the GNSS network infrastructure is largely fit-for-purpose although White Island and Taranaki are highlighted as needing greater instrumentation.

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2.3.3 Hardware Requirements

The following changes to network infrastructure are recommended.

• Greater geodetic instrumentation at White Island. Currently, the constraints on ground deformation at White Island are limited to quarterly levelling surveys and one continuous GNSS station; this does not allow good time series analysis for short term variations in ground deformation.

o 2-3 extra GNSS stations at White Island.

o Borehole tilt at White Island.

o Campaign GNSS for White Island using existing hardware.

o Campaign gravity for White Island using existing hardware.

• Greater geodetic instrumentation at Taranaki. Currently only one GNSS station distant to the mountain exists. It is recommended 3-4 additional stations are installed to provide basic detection and modelling capability. In the future denser network coverage would also provide some insights into flank stability. Future GNSS stations should have borehole tilt or strain colocated.

• Fast sampling (1Hz or greater) of all continuous geodetic data streams.

• Faster streaming (low latency) of GNSS at selected sites initially.

• Borehole strainmeters. Strain measurements are mostly based on GNSS data currently and borehole strain would be a useful addition to this. The first task is to review the long term viability of borehole strain by assessing other international installations. Borehole strain instrumentation would be best applied in conjunction with other instruments, i.e. co-located with GNSS, tilt and BB seismic instruments.

• Longer baseline tiltmeters. Long baseline tiltmeters reduce the effects of near surface noise and temperature fluctuations allowing very small signals to be measured.

• Borehole tiltmeters close to active vents. Signals from changes in shallow hydrothermal systems may be small and not detectable by instruments distant from the source. Borehole rather than surface instruments are preferred, to improve signal to noise by reducing the effects of near surface temperature variations.

• Co-located BB seismometers, tiltmeters and GNSS are useful to model the full spectrum of ground motion.

2.3.4 Processing and Analysis Methods

As with seismic data, analytical techniques need to be improved to provide higher quality processed data in near real-time. The following recommendations should be implemented over the next 3-5 years.

• Routine implementation of software tools for modelling mass distribution within volcanic systems to allow shallow hydrothermal processes and deeper magmatic processes to be distinguished.

• Streamlined processing and inversion of geodetic datasets when suitable signals are measured.

• Improvements to communications networks to allow real time transmission of 1 and 10Hz

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GNSS data. Currently 1Hz data are streamed from some stations but 10Hz data are only stored on board the receiver and are manually downloaded as needed.

• Improved GNSS analysis software for processing data with higher sampling rates.

• Improved correction of meteorological disturbances to GNSS data.

• Modelling of both GNSS and seismic data at higher rates concurrently.

Moving towards higher rate data solutions is currently possible. This is the first step toward detection and modelling of high rate events such as slow slip or intrusion of magma. Modelling of such events in near real-time time is more challenging and may need some development.

2.3.5 Summary

Geodetic respondents highlighted the need for a more diverse range of geodetic instrumentation and faster sampling rates. These will allow more accurate inversion of results enabling better discrimination between magmatic and hydrothermal processes. White Island in particular was singled out as needing a greater range of geodetic techniques and Taranaki was highlighted as needing more continuous GNSS stations.

2.4 General Geophysics

There are a subset of general geophysics techniques that may have some application to volcano monitoring. They are techniques that should be developed through research projects, possibly in conjunction with students, before their suitability for use in New Zealand can be demonstrated and subsequently be used within GeoNet. These techniques include muon imaging (Macedonio et al. 2010), continuous or campaign gravity measurements (de Zeeuw-van Dalfsen et al. 2006; Williams-Jones et al. 2008) and continuous or campaign electrical and magnetic measurements, including self potential, magnetotelluric, resistivity (Bennati et al. 2011; Revil et al. 2011).

2.5 Geochemistry and Hydrogeology

Submissions can be divided into groups covering (a) degassing, (b) crater lake monitoring; and (c) hydrological monitoring. These are discussed individually in sections below.

Written submissions were received from Agnes Mazot, Bruce Christenson and Magali Moreau with further input from Craig Miller, Brad Scott, Gil Zemansky, Karen Britten, Tony Hurst, Nico Fournier at the follow up meeting.

2.5.1 Degassing

2.5.1.1 Aims

Measurements of volcanic gases (commonly CO2, SO2 and H2S) are able to provide us insights into the state of magma reservoirs beneath volcanoes (Werner et al. 2011), (Inguaggiato et al. 2011). Changes in gas emission rates may precede volcanic eruptions and are therefore useful to monitor on a frequent basis. Emission rates may also vary if the gases interact with hydrothermal systems or crater lakes on their way to the surface (Werner et al. 2006). These water/gas interactions can make deciphering the surface emission results more difficult and so improving our models that describe them is a fundamental goal.

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Long term, high frequency time series are useful in defining natural background variation so that anomalous emission rates which may represent volcanic unrest can be more easily identified.

2.5.1.2 Overview of Submissions

Four themes relating to volcano degassing were identified. Common themes of the degassing submissions were higher sampling rates and sampling a more diverse range of species. These were aimed at better quantifying degassing behaviours at short time scales. Many degassing trends are cyclic and we may be aliasing them with our current sampling regime. C and S emissions are already being done at monthly or less intervals and should continue but more frequent (minutes to hours) measurements would be useful.

We want to be better able to quantify the flux of volatiles through volcano hydrothermal systems so we can better understand how the magmatic system behaves at depth.

8) More continuous gas measurements

There should be an aim of moving towards measurements being made (and processed) at least hourly for key species such as CO2 and SO2.

9) Expand airborne platform to include aerosol sampling.1

10) Enhanced capability for campaign measurements for CO2 (laser diode) and other species using FTIR, although this should be seen as a step towards continuous measurements in the mid to long term.

11) Development of geochemistry eruption response equipment (SO2 camera, thermal imagery camera, portable DOAS).

12) Extending analytic capability of existing volcanic gas lab to allow for more robust measurement of dissolved gases.

Most themes require the development of additional hardware as listed below.

2.5.1.3 Hardware Requirements

Hardware requirements can be divided into a) field sensors and b) lab equipment.

1 Note: As of March 2012 this has been constructed and is operational.

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2.5.1.3.1 Field Sensors

• High rate gas measurements (CO2, SO2, H2S). Currently these measurements are mostly performed on a monthly basis potentially aliasing trends occurring at shorter timescales. If high rate measurements can be performed using remotely installed instrumentation then more detailed analysis can be undertaken allowing better quantification of gas flux. It is currently possible to measure SO2 in a semi continuous manner and this is being done at White Island. High rate measurements of other gases are more difficult and appropriate technology doesn’t yet exist.

• Meteorological data to accompany gas measurements is important to help quantify flux rates and correlate the influence of short term weather variations on gas flux measurements.

• New chemical sensors (Radon, CO2, CO). Develop of new chemical sensors to measure these species will help characterise gas emissions from a greater range of sources leading to a more complete understanding of volcanic degassing.

• Instrument fumarolic discharges (record P and T changes). Onsite recording of pressure and temperature changes of fumaroles will allow for greater understanding of the dynamics of these discharges which often provide direct links to the deeper magmatic system.

• Aqueous CO2 sensor and ambient CO2 at Ruapehu Crater Lake to provide a more continuous time series of CO2 degassing from Ruapehu volcano.

• Shorter term “campaign” measurements with Laser Diode and Fourier Transform Infra Red (FTIR) spectroscopy to increase the range of analytes available.

• Eddy covariance measurements of CO2 to complement other CO2 degassing measurements.

• Most instruments should be developed to deliver near real-time data.

2.5.1.3.2 Lab Equipment.

• Additional lab instrumentation to allow for more robust measurement of dissolved gases.

• Cryogenic stage in the gas lab to better separate dissolved gases from water samples.

• Ultrasonicator for gas lab for better dissolved gas analysis.

2.5.1.4 Summary

More frequent sampling (semi continuous measurements) and new instrumentation to analyse a wider range of species are needed to help better characterise short term emission rate variations. Currently our 4-6 week sampling of gases probably aliases many short term trends and makes short term hazard assessment difficult. More frequent (semi continuous) measurements would make understanding the background variation of emissions easier allowing for more accurate recognition of anomalous conditions. These will provide better input into models to improve understanding of the processes driving geochemical changes at volcanoes. Such modelling takes a longer time and relies on long time series.

2.5.2 Crater Lake Monitoring

2.5.2.1 Aims

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Crater lakes often obscure deeper magmatic signals, hence understanding the hydrothermal system dynamics will allow us to better quantify changes in the magmatic system (Werner et al. 2008).The crater lakes act as a filter on the magmatic system and understanding this filtering process will improve our interpretation of the magmatic “source” signal (Mazot et al. 2008). New Zealand’s two most active volcanoes (White Island and Ruapehu) both contain crater lakes, so understanding crater lake systems is a primary goal in New Zealand volcanology.


Two themes around crater lake monitoring were developed. One recommends the instrumentation of crater lakes and large scale geothermal features with dataloggers recording basic physical properties. The other recommends an upgrade in lab facilities to improve gas extraction methods for water samples of all types. This could include analysing gases in groundwater wells and fault zone fluids, which might be useful precursors to eruption. The lab facility requirements are discussed in section 2.5.1.3.

13) Telemetered data logging of crater lake physical parameters such as lake level, temperature and overflow rate.

Development of additional sensors for chemical and gas analysis that can be logged at the same time.

Possible crater lake sites suitable for data logging include:

• Waimangu – Frying Pan and Inferno Lakes (Temperature and level already in progress).

• Mt Ruapehu (Temperature and level already in operation).

• White Island.

• Raoul Island (Temperature and level already in operation).

2.5.2.3 Hardware requirements

• Low rate (1 sample per hour) sampling of physical parameters is suitable for the rates of change commonly observed at crater lakes.

• Parameters to record include the lake temperature, water level and overflow rate. These parameters provide the basis of calorimetery and mass budget calculations. Logging crater lake overflow rates can be achieved by installing weirs over outlets and logging the overflow level.

• Chemical parameters to record include lake water pH and conductivity.

• Recording of meteorological parameters is important for quantifying external inputs (rain) into crater lake systems and also to help determine evaporation rates which form parts of calorimetric calculations.

• Instrumentation for measuring dissolved CO2 in crater lake water. “Microgas” sensors are currently being developed which could have future application. They will be cheap and disposable, potentially measuring CO, CO2 and halogen gases. Gas phase chemistry is probably more interesting than the water chemistry.

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• Acoustic hydrophones for gross gas output (bubbles).

• Telemetry of data should be used if possible but if the site is out of telemetry coverage, data should still be recorded on site and manually downloaded on a regular basis.

2.5.3 Hydrogeology

2.5.3.1 Aims

Hydrogeology in a volcanological context is aimed at using aquifers as potential sources of information about changes in stress regimes in volcanic areas (through water level changes) and changes in aquifer chemistry which may indicate magmatic influences (Shibata et al. 2008, Itaba et al. 2007).


One key topic area for hydrogeology was highlighted: using existing water wells for detecting regional strain changes.

14) Develop a catalogue of existing wells (and other hydrologic features) around volcanoes that would be useful to monitor for long term changes.

Changes in well water levels in the vicinity of a volcano may be related to strain changes, as a result of tectonic interactions of magmatic intrusions. Currently, regional councils collect these data for monitoring groundwater reserves and quality. Some of the data are automated, although the measurements are predominantly made manually every few months. This information is generally freely available for use.

The first priority should be to investigate what is actually available in each area and assess if it is suitable for volcano purposes.

Three levels of study would be envisaged: at a regional scale for tectonic strain changes; at local scale for aquifers that may influence slope stability and at a small scale for crater lakes and related hydrothermal systems.

Geophysical methods such as resistivity, self-potential and gravity could also be used to delineate groundwater changes. This is related to section 2.4: General Geophysics.

2.6 Physical Volcanology

Submissions for this discipline are divided into the following groups: (a) ash; (b) remote sensing of plumes; and (c) lahar. An additional section on hazard forecasting is included here for completeness. There is some overlap in the ash and plume sensing groups but here the division is made based on ashfall on the ground vs. ash transport in the atmosphere.

Written submissions were received from Gill Jolly, Mike Rosenberg, Tom Wilson, Ben Kennedy, Vern Manville, Graham Leonard, Dougal Townsend. A follow-up meeting was attended by Brad Scott, Craig Miller, Tony Hurst, Mike Rosenberg, Graham Leonard, Tom Wilson, Ben Kennedy. Written responses were received from Gill Jolly and Laura Sandri relating to using Bayesian Event Trees for quantifying hazard levels with changing monitoring parameters. One submission on geochronology, stratigraphy and mapping (Leonard,

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Rosenberg and Townsend) was mostly related to research work not directly applicable to GeoNet monitoring.

2.6.1 Ash

2.6.1.1 Aims

Volcanic ashfall poses a serious problem to health and infrastructure during times of volcanic eruption. Even small amounts of ash (a few mm) can disrupt power supplies, telephone lines, waste water treatment plants, airline travel and cause respiratory problems. Ash can also lead to contamination of water supplies and crops (http://volcanoes.usgs.gov/ash/index.html). Knowing the distribution, thickness and composition of ash during an eruption is therefore important so that preventive measures can be undertaken to minimise the effects of ashfall on communities.

2.6.1.2 Overview of submissions

Most of the physical volcanology submissions focused around volcanic ash – predicting its location on the ground and in air following an eruption, collecting samples and follow-up analysis. Most of this work requires cooperation with agencies external to GNS (Metservice and universities) for it to function effectively.

The following high level themes were developed.

15) Ensure access to external lab facilities required for ash analysis is available at short notice in times of eruption (includes university labs, NIWA labs and other labs in New Zealand and overseas).

16) Continue to develop the ash analysis protocol and develop ash collection procedures to ensure consistency among diverse groups likely to be collecting ash and ensuring international best practice is followed.

17) Implementation of public ashfall reporting capability utilising software developed in the U.S.

Some of the work done as part of current research projects is also the same work that would be done in an eruption response mode. However, the eruption response role would require quick access to the necessary lab facilities to undertake the necessary analysis.

Ash collection protocols are in development by GNS Science and University of Canterbury and most of the necessary sampling equipment already exists. Ash collection protocols are needed as different organisations could be involved in ash collection and all would need to be operating using the same procedures to ensure sample consistency. There is also a wide variety of “end users” of ash, for example, health, infrastructure, geological, and experimental, so collection and analysis procedures should take this into account.

http://volcanoes.usgs.gov/ash/index.html

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In conjunction with ash collection there is also the opportunity for developing a public reporting procedure. The Alaskan Volcanoes Observatory has implemented a successful web-based system (http://avo.alaska.edu/ashreport.php) which could be adopted for use in NZ. Use of the internet to gather ashfall data also allows feedback from and to the public to increase awareness. It is recommended that software that has been already developed or installed at other observatories be used to collect ashfall information in New Zealand via the GeoNet website. These ashfall reports would allow near real-time isopleth maps and likely effects.

2.6.2 Plume Remote Sensing

2.6.2.1 Aims

Volcanic ash in the atmosphere poses a major hazard for aviation and can lead to widespread disruption of air travel with associated economic impacts (Bolic et al. 2011). The aim of plume remote sensing is to provide accurate and fast (within minutes of an eruption) information on ash cloud dispersal during a volcanic eruption.


The following high level themes were developed. These themes are somewhat interlinked and require multiagency cooperation to fully achieve.

18) Remote sensing of volcanic plumes and ground based flows is required to better constrain eruption dynamics to inform hazard assessment.

19) Remote sensing may require further development of relationships with external agencies, for example, plume dispersal is carried out by Metservice rather than GNS.

20) The current ashfall and dispersal models should be reviewed in collaboration between GNS and Metservice. We could use eruptions in the SW Pacific to test models, although this should be undertaken through research in the first instance before being used in GeoNet.

Quantifying the eruption rate is also important for constraining plume models. Methods to determine this mostly require proximal vent access with high speed cameras etc, which could be logistically difficult. Massey University have a Doppler radar installed at Ruapehu. This has short range (<5 km) and is intended to capture ballistics and ash emission rates and provide information on shallow volcanic processes and their relationships with surface activity. This method has proven useful at other volcanoes (for example at Stromboli (Gouhier et al. 2010) and Arenal (Valade et al. 2011)) but has yet to be tested in New Zealand. In Alaska and Iceland, longer range weather radar (> 150 km), is utilised (Marzano et al. 2011) but is expensive and large. This could be considered if a volcano enters a period

http://avo.alaska.edu/ashreport.php

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of extended activity. The use of satellite data allows tracking plumes beyond the range of ground based radar. A range of satellites are utilised for plume tracking and a brief user guide is given here; http://vhub.org/topics/SatelliteMonitoring (Carn 2012).

A wider issue of developing techniques to monitor plumes when there are currently no eruptions in progress is highlighted. Overseas volcanoes (e.g. Vanuatu) could be used to develop such expertise, but would need funding from research programmes. Given recent eruptions in Europe and Chile there is likely to be a high emphasis on plume and ash tracking because of its implications on aviation. Currently the Metservice handle this role but collaboration should be developed to enable exchange of information during a crisis.

Currently, GNS Science uses ASHFALL for forecasting tephra distribution, but there is more modern software (such as TEPHRA2). Other software should be investigated and output should be improved, possibly to include probabilistic forecasts.

Ongoing hazard assessment of land close to the volcano would rely on quantifying changes to topography around the volcano. Catchment volume changes and their capacity to transport material away from the volcano could be quantified, allowing hazard maps to be updated as a long lived eruption progressed.

Ground based Infrared cameras also allow detection and quantification of volcanic ash (Prata et al. 2009), and changes in shallow thermal structure of volcanoes (Chiodini et al. 2007). Modern cameras are equipped with telemetry capabilities allowing real-time transmission of images back to the observatory.

2.6.2.3 Hardware Requirements

As mentioned above, significant hardware purchases might be needed to fulfil all possible requirements during an eruption. It is unrealistic to consider capital cases for all these under GeoNet unless an eruption is ongoing. In the meantime, use of these items should be developed under research programmes in the first instance also recognising that capability development takes time after the purchase of the capital item.

• Doppler Radar for ash and ballistics detection close to the eruption site. Sizes of ballistics and the mass of ash plumes close to the vent can be determined, which may provide inputs into atmospheric modelling and monitoring of tephra dispersal.

• Satellite remote sensing (ash, thermal, visible). Nasa’s “A” train satellites (Aqua, CALIPSO, CloudSat and Aura) provide the ability to provide coincident, multispectral, multispectral, active and passive remote sensing data for volcanic clouds. Ready access to data from these satellites would be useful during an eruption.

• Repeat topographic surveys using Lidar to determine changes in catchment volumes which may result in changes to the ongoing eruption hazard as well as the long term flooding hazard once the eruption has ceased.

• IR cameras (both portable and fixed for web transmission) for mapping thermal changes to volcanic edifices.

Most of these tools are only useful during an eruption, but if they are not in place or the capability to analyse the data is not available, it is difficult to collect appropriate data when an eruption starts. In the Icelandic eruptions in 2010, this was partly solved by collaborating

http://vhub.org/topics/SatelliteMonitoring

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closely with overseas partners, and this may be an option for New Zealand in the future. Accurate topography of the volcanic areas is also needed prior to an event starting to enable volume changes to be determined. Thus Lidar coverage should be supported where possible, although it is not recommended that GeoNet or GNS Science initiates collection of such data.

2.6.2.4 Processing / analysis methods

Using data collected from this hardware as input, modelling codes such as Titan2D or PyroFlow for Pyroclastic Density Currents (PDC) can be used in a crisis to provide near-real time hazards estimates. There are many other hazards models available for ash fall, lava flows, dome growth and other phenomena, but the capability is not present in New Zealand to operate all possible software.

2.6.2.5 Summary

The availability of appropriate remote sensing hardware is the main theme of respondents. Much of this hardware would only be of use during an eruption. The setting up of a dedicated ash fall reporting website as part of the GeoNet website would be a very useful addition in times of an eruption. Greater co-operation between GNS and the Metservice for ash fall and dispersion modelling is recommended.

2.6.3 Lahar

2.6.3.1 Aims

Lahars represent a significant hazard in New Zealand and have produced fatalities and infrastructure costs to New Zealand in the past century. Ruapehu is currently monitored using a lahar detection system ERLAWS which is maintained and operated by Department of Conservation. Should GeoNet improve lahar monitoring capabilities in the future, the following guidelines may provide a baseline for this work.

2.6.3.2 Overview of submissions

One submission for lahar monitoring was received from Vern Manville. This submission was predominantly research oriented and discussed scope to develop the capability to confirm and characterise lahars in critical catchments. For Ruapehu, this is already achieved through ERLAWS, which has recently been upgraded through a joint project between DOC, Genesis, Massey University and Horizons Regional Council.

There are two key areas for future lahar response: Ruapehu after a major (cf. 1995/6) eruption and Taranaki rainfall and future eruption events. Currently only the Whangaehu catchment on Ruapehu is monitored specifically for lahars although some Taranaki catchments are monitored for rainfall events by the regional council. It should be noted that landslide response is currently a GeoNet response activity.

Data collected will yield information on the magnitude, sediment concentration, and downstream hydrodynamic evolution of lahars at Ruapehu triggered by a variety of mechanisms, including eruptions through Crater Lake, rain-triggered events, and lake break-outs. Two lahar-prone regions should be instrumented: (1) The Whangaehu valley; (2) The Whakapapa ski field. Location at previously utilised sites will permit continuity with historical records. Not all of these sites require the same level of instrumentation. Co-location with

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existing agency infrastructure should be investigated.

2.6.3.3 Hardware requirements

• Vibration sensors: both acoustic flow monitors/geophones and broadband seismometers are suitable.

• Non-contact (ultrasound or radar) stage gauges to measure flow height.

• Sub-bed pore pressure transducers and earth pressure cells to measure flow depth, and potentially density and erosion/deposition rates.

• Triggered camera systems (digital still, video, or webcam), with associated IR floodlighting.

• pH and conductivity probes at downstream sites to measure water quality as a proxy for mixing of Crater Lake water with ambient river.

• Pre- and post-event characterisation of channel geometries at monitoring sites using Terrestrial Laser Scanning.

• Pressure-plate and impact counters on the leading edges of bridge piers and the OnTrack gauge to obtain data on dynamic lahar forces, sediment load and vertical concentration profile in active flows.

Some of this equipment is already installed in the Whangaehu catchment and operated by other agencies.

2.6.4 Hazard Forecasting

2.6.4.1 Aims

Bayesian Event Trees (BET) are increasingly used in natural hazards to calculate the probability of any kind of long-term hazardous event, accounting for the intrinsic stochastic nature of volcanic eruptions and our limited knowledge regarding related processes (Marzocchi et al. 2010). This leads us to being able to quantify changes in volcanic hazard based on changes in monitored parameters with the aim of producing short and long term forecasts of activity which can be useful in many practical aspects for land use planning and volcanic emergencies (Marzocchi et al. 2008).

2.6.4.2 Summary of submissions

Responses were received from Gill Jolly and Laura Sandri. Setting up of BET codes requires the availability of comprehensive monitoring datasets and eruption histories to use as input data from which probability calculations for future events can be made. Multiparameter time series monitoring data and networks of monitoring instruments are required to provide current information so that short term forecasts can be produced in accordance with changes in monitoring data. It is necessary to setup BET codes in advance so that changes in monitored parameters can be readily input to determine changes in hazard. The setting of thresholds of these data is also important. Much of the background information needed can be provided through externally funded geological research programs so the challenge is to ensure the flow of that information through to the monitoring team.

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3.0 CONCLUDING REMARKS

The researcher consultation process has highlighted some topics that were not revealed in the NVEWS methodology, as the latter focuses mainly on instrumentation. This has shown the usefulness of direct consultation with the research community to augment the NVEWS methodology.

The routine use of advanced processing techniques for seismic and geodetic data were recommended with only minor improvements to network infrastructure at White Island and Taranaki required to make full benefit of these techniques.

Future geochemical techniques are focussed on acquiring higher rate data (of multiple gas species) to better understand degassing trends. Higher sample rate, multiple sensors and telemetry of data loggers were also recommended for Crater Lake monitoring. A programme to identify suitable waterbores for waterlevel monitoring (as a proxy for strain) was identified as useful for all volcanoes.

Several topics on ashfall collection, analysis and public interaction via website ashfall reports were developed and would operate between GNS Science and NZ universities. A review of NZ’s ash plume modelling capability (shared between GNS Science and Metservice) was also suggested.

Recommendations for lahar monitoring were put forward and should be considered in the context of existing capabilities, monitoring and other funding priorities.

The greater use of hazard forecasting techniques (Bayesian Event Trees) was recommended. This requires the input of both eruption history data provided by research programmes and also the establishment of volcano system models for each volcano so that unrest scenarios can be developed and event probabilities calculated. Ensuring that links between GeoNet and the research community are maintained in the future is important to achieve this objective.

It is hoped that the feedback presented in this report will be useful for the future GeoNet review and may play some part in shaping the future direction of volcano monitoring in New Zealand.

4.0 ACKNOWLEDGEMENTS

Thanks to all the participants for sharing their views on the future direction of GeoNet funded volcano monitoring in New Zealand.

5.0 REFERENCES

Battaglia, M. and D. P. Hill (2009). "Analytical modeling of gravity changes and crustal deformation at volcanoes: The Long Valley caldera, California, case study." Tectonophysics 471(1-2): 45-57.

Bennati, L., A. Finizola, et al. (2011). "Fluid circulation in a complex volcano-tectonic setting, inferred from self-potential and soil CO2 flux surveys: The Santa Maria-Cerro Quemado-Zunil volcanoes and Xela caldera (Northwestern Guatemala)." Journal of Volcanology and Geothermal Research 199(3-4): 216-229.

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Bolic, T. and Z. Sivcev (2011). "Eruption of Eyjafjallajokull in Iceland Experience of European Air Traffic Management." Transportation Research Record(2214): 136-143.

Bonanno, A., M. Palano, et al. (2011). "Magma intrusion mechanisms and redistribution of seismogenic stress at Mt. Etna volcano (1997-1998)." Terra Nova 23(5): 339-348.

Carn, S. (2012). Volcanic clouds observed by the A-Train satellite constellation.

Chadwick, W. W., Jr., S. Jonsson, et al. (2011). "The May 2005 eruption of Fernandina volcano, Galapagos: The first circumferential dike intrusion observed by GPS and InSAR." Bulletin of Volcanology 73(6): 679-697.

Chiodini, G., G. Vilardo, et al. (2007). "Thermal monitoring of hydrothermal activity by permanent infrared automatic stations: Results obtained at Solfatara di Pozzuoli, Campi Flegrei (Italy)." Journal of Geophysical Research-Solid Earth 112(B12).

de Zeeuw-van Dalfsen, E., H. Rymer, et al. (2006). "Integration of micro-gravity and geodetic data to constrain shallow system mass changes at Krafla Volcano, N Iceland." Bulletin of Volcanology 68(5): 420-431.

Dzurisin, D. (2007). Volcano Deformation. Geodetic Monitoring Techniques, Springer.

Ewert, J. W., Guffanti, M., Murray, T. (2005). An Assessment of the Volcanic Threat and Monitoring Capabilities in the United States: Framework for a National Volcano Early Warning System. Open File Report 2005-1164, USGS.

Gouhier, M. and F. Donnadieu (2010). "The geometry of Strombolian explosions: insights from Doppler radar measurements." Geophysical Journal International 183(3): 1376-1391.

Hagerty, M. and R. Benites (2003). "Tornillos beneath Tongariro Volcano, New Zealand." Journal of Volcanology and Geothermal Research 125(1-2): 151-169.

Hurst, A. W. and S. Sherburn (1993). "VOLCANIC TREMOR AT RUAPEHU - CHARACTERISTICS AND IMPLICATIONS FOR THE RESONANT SOURCE." New Zealand Journal of Geology and Geophysics 36(4): 475-485.

Inguaggiato, S., A. Mazot, et al. (2011). "Monitoring active volcanoes: The geochemical approach." Annals of Geophysics 54(2): 115-119.

Itaba, S. and N. Koizumi (2007). "Earthquake-related changes in groundwater levels at the Dogo hot spring, Japan." Pure and Applied Geophysics 164(12): 2397-2410.

Jolly, A. D., J. Neuberg, et al. (2012). "A new source process for evolving repetitious earthquakes at Ngauruhoe volcano, New Zealand." Journal of Volcanology and Geothermal Research 215: 26-39.

Jolly, A. D., S. Sherburn, et al. (2010). "Eruption source processes derived from seismic and acoustic observations of the 25 September 2007 Ruapehu eruption-North Island, New Zealand." Journal of Volcanology and Geothermal Research 191(1-2): 33-45.

Macedonio, G. and M. Martini (2010). "Motivations for muon radiography of active volcanoes." Earth Planets and Space 62(2): 139-143.

Marzano, F. S., M. Lamantea, et al. (2011). "The Eyjafjoll explosive volcanic eruption from a microwave weather radar perspective." Atmospheric Chemistry and Physics 11(18): 9503-9518.

Marzocchi, W., L. Sandri, et al. (2008). "BET_EF: a probabilistic tool for long- and short-term eruption forecasting." Bulletin of Volcanology 70(5): 623-632.

Marzocchi, W., L. Sandri, et al. (2010). "BET_VH: a probabilistic tool for long-term volcanic hazard assessment." Bulletin of Volcanology 72(6): 705-716.

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Mazot, A., A. Bernard, et al. (2008). "Chemical evolution of thermal waters and changes in the hydrothermal system of Papandayan volcano (West Java, Indonesia) after the November 2002 eruption." Journal of Volcanology and Geothermal Research 178(2): 276-286.

McNutt, S. R. (2005). Volcanic seismology. Annual Review of Earth and Planetary Sciences. 33: 461-491.

Miller, C. A. (2011). Threat assessment of New Zealand's volcanoes and their current and future monitoring requirements GNS Science Report, GNS Science.

Mordret, A., A. D. Jolly, et al. (2010). "Monitoring of phreatic eruptions using Interferometry on Retrieved Cross-Correlation Function from Ambient Seismic Noise: Results from Mt. Ruapehu, New Zealand." Journal of Volcanology and Geothermal Research 191(1-2): 46-59.

Poland, M., M. Hamburger, et al. (2006). "The changing shapes of active volcanoes: History, evolution, and future challenges for volcano geodesy." Journal of Volcanology and Geothermal Research 150(1-3): 1-13.

Prata, A. J. and C. Bernardo (2009). "Retrieval of volcanic ash particle size, mass and optical depth from a ground-based thermal infrared camera." Journal of Volcanology and Geothermal Research 186(1-2): 91-107.

Revil, A., A. Finizola, et al. (2011). "Hydrogeology of Stromboli volcano, Aeolian Islands (Italy) from the interpretation of resistivity tomograms, self-potential, soil temperature and soil CO(2) concentration measurements." Geophysical Journal International 186(3): 1078-1094.

Roman, D. C., S. De Angelis, et al. (2008). "Patterns of volcanotectonic seismicity and stress during the ongoing eruption of the Soufriere Hills Volcano, Montserrat (1995-2007)." Journal of Volcanology and Geothermal Research 173(3-4): 230-244.

Segall, P. (2010). Earthquake and Volcano Deformation, Princeton University Press.

Shibata, T., F. Akita, et al. (2008). "Hydrological and geochemical change related to volcanic activity of Usu volcano, Japan." Journal of Volcanology and Geothermal Research 173(1-2): 113-121.

Titzschkau, T., M. Savage, et al. (2010). "Changes in attenuation related to eruptions of Mt. Ruapehu Volcano, New Zealand." Journal of Volcanology and Geothermal Research 190(1-2): 168-178.

Valade, S. and F. Donnadieu (2011). "Ballistics and ash plumes discriminated by Doppler radar." Geophysical Research Letters 38.

Werner, C., B. W. Christenson, et al. (2006). "Variability of volcanic gas emissions during a crater lake heating cycle at Ruapehu Volcano, New Zealand." Journal of Volcanology and Geothermal Research 154(3-4): 291-302.

Werner, C., T. Hurst, et al. (2008). "Variability of passive gas emissions, seismicity, and deformation during crater lake growth at White Island Volcano, New Zealand, 2002-2006." Journal of Geophysical Research-Solid Earth 113(B1).

Werner, C. A., M. P. Doukas, et al. (2011). "Gas emissions from failed and actual eruptions from Cook Inlet Volcanoes, Alaska, 1989-2006." Bulletin of Volcanology 73(2): 155-173.

Williams-Jones, G., H. Rymer, et al. (2008). "Toward continuous 4D microgravity monitoring of volcanoes." Geophysics 73(6): WA19-WA28.

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APPENDICES

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APPENDIX 1 – LIST OF RESEARCHERS WHO WERE SENT QUESTIONAIRES

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In Alphabetical order

Stephen Bannister John Beavan

Kelvin Berryman Ted Bertrand

Grant Caldwell Bruce Christenson

Jim Cole Jeremy Cole-Baker

Shane Cronin Susan Ellis

Nico Fournier Bill Fry

Darren Graveley Graham Hill

Bruce Houghton Tony Hurst

Art Jolly Gill Jolly

Ben Kennedy Geoff Kilgour

Graham Leonard Shaun Levick Jan Lindsay Gert Lube

Vern Manville Agnes Mazot Craig Miller

Magali Moreau Mahdi Motagh John Proctor

Martyn Reyners Mike Rosenberg

Laura Sandri Martha Savage

Brad Scott Steve Sherburn

Pilar Vilamor Laura Wallace Colin Wilson Tom Wilson

Gil Zemansky

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APPENDIX 2 – INDIVIDUAL SUBMISSION RESPONSES

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Submission title: Short-term variations in volatile emissions from New Zealand volcanoes

Researchers’ names: Bruce Christenson, Agnes Mazot, Karen Britten, Joan Fitzgerald

What is your proposed research?

We propose to study short term behaviour of magmatic exhalatives from New Zealand's active volcanoes, with a view to increasing our understanding of processes operating at the magmatic-hydrothermal interface. We know for certain that longer-term variations exist which point to the major changes in the hydrothermal architecture of these systems, but we know very little about the shorter term fluctuations, and what they can tell about physico-chemical processes operating in the conduit regions. As one of the major goals of FRST-funded research over the coming 3 years is to understand the big-picture magmatic degassing processes of White Island and Ruapehu, it is critical that we understand as best we can the processes operating at the magma-hydrothermal interface so that these can be accounted for.

What types of data are required for this research?

A number of data streams are required:

1. Instrument fumarolic discharges with logging P and T sensors to observe what, if any, short term variations exist in these parameters.

2. Instrument Ruapehu Crater Lake and ambient outlet atmosphere with continuous monitoring capability for aqueous CO2. This will go some distance toward "filling in the gaps" in our knowledge of CO2 degassing processes for this volcano for which we presently have one measurement every 4 to 6 weeks.

3. Short-term conventional sampling/analysis of fumarolic discharges.

4. Short-term (6-8 hour) monitoring sessions of volatile emissions from lakes, fumaroles and vents using a combination of laser-diode and FTIR systems which will greatly increase the range of analytes.

What results can be achieved with the collected data?

The results will include a much-improved understanding of the processes operating at the magma-hydrothermal interface, and therefore an enhanced ability to interpret the emissions from these volcanoes.

What are the timeframes for deriving the results and how can they be used to inform monitoring for volcano hazards?

Analytical results will be retrieved in near-real time, and will become part of part of the emissions database against which new results are compared and interpreted, and risks assessed.

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How can the field collection of this data be improved?

Installations of assorted field equipment will be required (temperature, pressure, CO2 sensors).

Purchase of laser diode and FTIR systems will be required.

What new trends and improvements may occur in the next 5-10 years?

I should think that within the next 5-10 years we should see accelerated advancement of technology which will foster more or less permanent deployment of instrumentation which will allow for real-time data collection referred to above.

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Submission title: Degassing models for New Zealand volcanoes

Researchers’ names: Bruce Christenson, Agnes Mazot, Karen Britten, Joan Fitzgerald


Sustained magmatic degassing at White Island and Ruahepu volcanoes demonstrate that both systems are connected to significant supplies of magma at depth. Using the existing GeoNet emissions database, we will conceptually evaluate two possible mechanisms (eg. magma convection, vs coupled-decoupled flow) that could account for the observed degassing characteristics of these volcanoes. To this end, we will evaluate mass balance models for the rate of delivery of magma into the "degassing zones" of the conduits of both Ruapehu and White Island, constrained by CO2 and SO2 emission, and we will incorporate metal emissions (aerosol) data as it becomes available from late 2010-11, and FTIR gas data as it comes available in 2011-12. With conceptual models in hand, we will then develop solubility-based algorithms which, along with petrological data, will provide constraints for depth of degassing.


Aerosol data, C and S emissions data and FTIR data.


The end goal is resolving the mode(s) of degassing at these volcanoes.


Timeframes for the research are laid out above. Any increase in understanding of the normal degassing modes of these volcanoes will underpin our interpretive framework for detecting and delineating their respective hazards during periods of unrest.


FTIR and OIRP hardware (Fourier Transform Infra Red spectrometer and Optical Infra Red Pyrometer, respectively) will be required for direct emissions analysis of vent gases. Both are identified as capex items for financial year 2011-12.

Airborne C and S measurements are already being made, and although small improvements can be gained through upgrading component hardware, the current situation is deemed adequate.

Distal airborne aerosol data collection is currently under development, and should be under way by the end of financial year 2010-11. This data collection will be done in tandem with the other airborne measurements, thus enabling bulk emission estimates of relevant analytes. Proximal aerosol collection at White Island will be required at some point so that the effects of sea aerosol can be factored out of the bulk (i.e., distal) measurements. Possible techniques for making these proximal collections are being investigated, and will

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probably involve some sort of remotely controlled unmanned airborne vehicle that can be operated on the crater floor, carrying filter packs into the proximal plume.


All of these undertakings are heavily technology-dependent, and while the technology is presently available to achieve all of the above goals, the 5-10 year timeframe will see ever-increasing improvement in gear, and a likely reduction in cost.

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Submission title: Trace Gas Analysis of Spring/Lake Waters

Researchers’ names: Bruce Christenson, Joan Fitzgerald


We have demonstrated that monitoring solute gas compositions in lake waters associated with active volcanic systems (eg., Ruapehu), is a useful tool for monitoring and understanding changes in the state of the underlying magmatic-hydrothermal interface.

To date, however, we have regarded our approach as preliminary, as we have been able to analyse only headspace gases evolved from waters taken into evacuated flasks. This relies heavily on theoretical corrections for the partitioning of gas between the headspace and the water phase in each sample in order to come up with a total solute gas composition for the water.

With a view towards improving the accuracy of the ongoing measurements, and extending the application of this technique to spring fluids (both cold and hot) across the TVZ and active fault zones, we feel it is time to make the analytical approach more rigorous.


To make these gas measurements more rigorous, we need to develop a system for stripping and trapping all dissolved gases from the sample liquid phase prior to analysis. There are techniques for doing this using ultrasonication of the water, and capturing the evolved gas for analysis on a cryogenic trap.

Our existing gas manifold was purposely designed for this modular expansion, and it simply becomes a matter of obtaining the ultrasonicator and cold trap, and plumbing them into the existing manifold.


We will be able to analyse virtually any aqueous phase for its dissolved gases. This applies to volcanic lakes and springs, and to waters recovered from springs or wells associated with faults.


The results would begin to flow immediately after commissioning of the hardware (this is not a lengthy process).

How can the field collection of this data be improved? N/A

What new trends and improvements may occur in the next 5-10 years? N/A

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Submission title: University of Canterbury Integrated Volcanology Program

Researchers’ names: Ben Kennedy, Tom Wilson, Darren Graveley, Jim Cole, The HiT (Human interface technology lab)

University of Canterbury

Hi GeoNet Volcano. We've put together an integrated questionnaire response which flags two areas of research we would like to explore and collaborate with you (A & B); and a broader interest in increasing the value of GeoNet inputs for geo-education to undergraduate, graduate and general public groups.

What is your area of research?

• Physical volcanology, quantifying eruption parameters. Scaled analogue and high temperature and pressure experiments. Pyroclastic flow dynamics Relationship between volcanism and hydrothermal systems.

• Volcanic ash dispersal. Volcanic ash physical and chemical properties.

• Volcanic hazard impacts on society (including risk management) and communication of hazard and monitoring information to end users (public and students)

• Non specific volcanological geo-education for graduate/undergraduate/ general public


All existing Geonet monitoring capabilities are useful to Canterbury researchers and students. VLPs GPS webcam tilt, gravity etc

We propose two areas where additional data/data management would be beneficial for building NZ’s volcanology monitoring capability:

A) Rapid deployment of earthquake triggered web cam and still camera array- with 3D visualisation capabilities for imaging eruptions (visible and infra red).

B) Web interface for scientist and public ash fall and ash impact reporting/mapping to allow near-real time isopach, isopleth and ‘likely effects’ (equivalent of EQ intensity) maps to be created (or calibrate ASHFALL models in real time or near-real time).


A) (i) Quantify ballistic velocities and trajectories and plume flux for plume modelling and pre-eruption pressure depth estimates. (ii) Measuring deformation using photo interferometry. (iii) Column collapse and pyroclastic flow development.

B) Improve quality and timeliness of isopach and isopleths and impact mapping. Strong research, emergency management and hazard/risk communication applications. Two key themes: i) develop volcano equivalent of the successful earthquake felt reports (quality control could be achieved through a log-in for scientists/trained members of the public); ii) maximise the utility and value of ash dispersal maps for end-users (thickness, projections, uncertainty; could be different lifeline utilities, CDEM, general public). Strong focus on using the communication lessons which GeoNet and other research outreach

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vehicles have learnt from the Canterbury earthquake – e.g. the estimated aftershock hazard maps. This strongly aligns with IACVEI Ash Impacts Working Group objectives.

C) Research and visual tools used for graduate and undergraduate student projects, classroom activities, and outreach.


A) Real time multi-angle images (video) of the velocities of ballistics and plumes can be processed within hours to days (within eruption episode). These images can then be translated into flux calculations which will inform the monitoring team and eruption modellers and likelihood of pyroclastic flow development.

Image pairs can also be compared to previous images to measure local deformation (centimetres- metres) -e.g. tumuli/dome growth. pyroclastic flow hazards.

B) Near real time ash mapping will significantly increase accuracy of ash fall dispersal models in an ongoing eruption crisis and achieve real time public outreach (similar to utility of “FELT” reports during Christchurch earthquakes). A similar approach was found to be highly beneficial for the Alaskan Volcano Observatory during the 2009 Redoubt eruption – both for public outreach/engagement and for reducing demands on field scientists collecting very thin (and thus perishable) ash deposits.

C) Student research and outreach is ongoing. Research will contribute to hazard models and education will provide capability for the future.


A) More web cams (infra red/ thermal and visible), deployed with 3D imaging, earthquake triggered data storage system,, using University of Canterbury HiT (Human Interface Technology) lab for image processing and 3D visualisation

B) Using the significant power of the internet/websites to improve collection and management of ash characteristics data (occurrence, thickness, colour, grainsize, etc) and impacts within the scientific community. In this capacity the GeoNet website could become a hub for data input, collate, and communication for groups ranging from expert users, Lifeline infrastructure, CDEM, media and the general public.

C) Better use of Canterbury student population for data collection, analysis and interpretation resulting in better collaboration.


A) More efficient real time data streaming, 3D visualisation, integration of thermal cameras and radar with imaging.

B) Volcano Observatories are increasing using their website as a hub for data collection, management and dissemination to end-users/stakeholders. Better ash impact data collection and management is a focus of IAVCEI Tephra Dispersal Modelling Commission and IAVCEI Ash Impacts Working Group.

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Submission title: Short-term transient volcano ground deformation modelling

Researcher’s name: Nico Fournier


High-rate ground displacement and tilt data. GPS and tiltmeter data with = or > 1Hz sampling rate. There are currently several GeoNet GPS stations monitoring ground displacement at the Tongariro National Park volcanoes. Apart from a few exceptions, there GPS stations mainly record at 30-sec epoch (i.e., 30-sec sampling interval). Higher-rate GPS data (e.g., 1Hz and above) available in real or near-real time would allow assessment of short term deformation episodes, especially at Ruapehu. Development of near source tiltmeters (maximum distance of 1’s km from the crater lake at Ruapehu) would ideally complement the high-rate GPS and may offer higher resolution for small amplitude ground deformation episodes.

Broadband seismic data can also detect transient tilt events and are being use as additional source of information.


Pressure source(s) characteristics can be retrieved from inverse modelling of the GPS and tilt data (e.g.., depth of the source, overpressure). This may allow to 1.detect and change in near surface at NZ volcanoes and 2. track the spatio-temporal evolution of pressure changes underground, whether it is related to magma moving or changes in the volcano hydrothermal system.

What are the timeframes for results and how can they be used to inform monitoring for volcano hazards?

• Rapid identification of pressurization in near-surface. This can be a major indication of imminent eruption.


Develop 1Hz - and above - GPS data recording and streaming. Development of borehole tiltmeters in the near field at Ruapehu and other volcanoes (1’s km from the active vent). Use of broadband seismometers on the volcanic edifice of composite cone volcanoes with a density of at least 2-3 stations, preferably less than 10 km from the active vent


Real-time processing may be developing over the next few years (will be tested at GNS over the next year). If it is viable from a communication and power perspective at remote GPS stations, it could be implemented as part of GeoNet operations (i.e., position at 1Hz or above, vs. the current daily position).

Semi-automated and near-real time data inversion could be designed to streamline the time bridge between data collection, processing and modelling.

2012


Submission title: Processes driving volcano ground deformation at White Island

Researcher’s name: Nico Fournier


Campaign levelling (currently every 3-months).

Campaign GPS data

Campaign gravity data

Continuous GPS data

Continuous gravity data

ContinuousTiltmeter data

Semi-continuous crater lake level and temperature


Numerical inversion of the 3-month interval levelling data allow a preliminary assessment of the characteristics (i.e., depth) of the source responsible for ground deformation at White Island volcano. The lack of constraints on the horizontal deformation is a limiting factor that may prevent us from determining whether the observed deformation is due to magmatic or hydrothermal processes. Additional GPS campaigns at the levelling benchmarks (ideally at 3-month interval) would allow far more control on the inversion process. Furthermore, regular gravity data from repeated campaign would identify potential changes of mass underground. This would provide invaluable information about the deformation source processes (e.g.., allow the discrimination between thermal response of the substratum and pressurization due to injected material – hydrothermal fluids or magma). Crater lake data can then be compared to assess potential links between underground mass changes and fluid transfer between the lake and the rest of the crater floor.

Continuous data (e.g., tilt, GPS and gravity) would provide control on the representativity of the 3-month campaign data and allow a full assessment of whether or not this campaigns interval is suitable for monitoring White Island volcano.


• Modelling results from gravity campaign can be available after two or three campaigns (i.e., ~ 1 year from the first campaign). These can be compared with the deformation data.

• Modelling results from GPS and levelling campaign can be available after two or three campaigns (i.e., ~ 1 year from the first campaign for the GPS).

2012



Include microgravity and GPS campaigns to the 3-month levelling surveys (at least every other survey).

Installation of 2-3 GPS receivers on the island, one of which co-located with a tiltmeter (e.g., platform or borehole).


Add other geophysical campaigns to the levelling, gravity and GPS to allow coupled geophysical inversions (e.g., gravity and magnetics, or gravity and displacement).

2012


Submission title: Volcanic cone deformation – Mt Taranaki

Researcher’s Name: Nico Fournier


Volcano deformation, volcano geophysics, physical volcanology


Primarily, continuously operating GPS stations. Other types of instrumentation could also be beneficial in case of volcanic unrest (e.g., 3 borehole tiltmeters or strainmeters)


Detection of volcanic unrest. Estimates of volume of magma intruding the edifice at depth through inversion of the geodetic data and numerical modelling.


Timescale of information from GPS daily positions is of the order of days/weeks to years, depending on the activity. Note that if the GPS stations stream high-rate data (e.g., 1-10Hz), and that Real-Time epoch-by-epoch processing is developed, deformation events may be detected at the scale of minutes to hours.


In order to get sufficient data to run some inversions, a minimum of 3 to 4 GPS stations detecting a potential ground deformation event is required. At Taranaki, this translates into adding a minimum of 3 stations on the edifice to be able to provide quantitative results.


Increase the number of GPS stations on the volcano (see above). In addition to ground deformation driven by volcanic processes, a denser network would also be able to provide some insights into flank stability.

2012


Submission title: Ambient Noise in volcanic systems

Researchers: Bill Fry and Art Jolly


Short period and broadband seismic data.


Passive seismic imaging based on noise cross-correlation allows imaging of surface wave velocities in areas with insufficient earthquake numbers and distribution to implement traditional earthquake based tomography. As surface waves are dominantly sensitive to shear wave speed, they can also be used to image the shear velocity (Vs). Another substantial advantage of passive imaging is the short duration of recording necessary to obtain stable images. This characteristic makes passive imaging an enticing choice for applications, such as volcanic monitoring, which require short time-scale dependent information. Two recent studies have shown the usefulness of seismic interferometry by using noise cross-correlations for detecting a time-dependent change in the velocity structure of a volcano before and after an eruption (Brenguier et al., 2008; Duputel et al., 2008).


• Relative velocity changes between station pairs may be achieved within a 1 day delay time, given pre-calculation of reference cross-correlation function.

• Absolute velocity changes could be achieved within weeks of data collection, given pre-calculation of surface wave velocity structure.

• 3D Tomographic inversion for surface wave/shear wave velocity structure to mid-crustal depths (10-15 km) can be achieved given existing GeoNet volcano station spacing and footprint for cone volcanoes (e.g. Ruapehu, Taranaki, Tongariro) can be achieved in months.

• The results can be used to inform hazards by identification of rapid crustal velocity changes beneath the volcanic edifice. Such information may be used to infer if processes are magmatic or non-magmatic in nature.

• Publication quality requires a 5 to 10 X multiplier for the above times for error checking, writing etc.


Ambient noise studies require at least two stations to obtain cross-correlation functions which might be used to obtain information about crustal velocity, or changes in the crustal velocity. Use of uniform instruments acts to reduce the amount of data required to achieve a stable cross-correlation function.

2012


What new trends and improvements may occur in the next 5-10 years

Advancements in noise analyses (eg. Use of cross convolution) might improve the stability of the empirical GF (Wapenaar et al., 2011; recent work by Andrew Curtis). Also, stationary phase (plane-wave) techniques have been shown to reduce the amount of correlation necessary to obtain dispersion measurements (Ekstrom 2008). The large scale velocity anisotropy may also be measured.

2012


Submission title: Crater Lake Studies

Researcher’s name: Tony Hurst


Crater Lake Studies


Regular ( preferably quasi-continuous) measurements of physical and chemical parameters in Ruapehu (and possibly other) volcanic crater lakes.


Indications of increase in heat flow from volcano or magma injection.


Logger data is recorded at 15 minute intervals, and is available hourly via satellite (although we routinely only get it daily). All chemical data currently about monthly by sample, with further delays for analysis.


More data by sensors attached to logger. A tiltmeter has recently been installed, and we’re currently working on a new hydrophone. The main need is for chemical sensors to detect ionic concentrations, including pH. We should be looking for sensors that offer a viable price/ruggedness/power combination that makes them suitable for Crater Lake.


New sensors, new communications, new understanding

2012


Submission title: Deformation Monitoring



Volcano Deformation monitoring


GPS Data. Other new techniques, e.g. Borehole strainmeters.


Indications of increase in pressure or magma injection.


Current GPS equipment is reasonable for timescales of a week or more. Any shorter timescale has problems, relating to network delays, meteorological disturbances and inability to reduce noise in current analysis techniques.


Improved radio/internet network


Cheap/Free availability of improved GPS analysis systems (to replace RTD)

Within this period expect new sensors to be available for borehole strain measurement. Also may be longer baseline tiltmeters (new generation of watertube tiltmeter).

2012


Submission title: Muon Tomography



Muon Tomography


Measurements of path and energy of cosmic ray muons as they pass through volcanoes.

We are applying for EQC funding to test this on Ruapehu/Ngauruhoe.

Reason for introducing this to Geonet workplan is that Ngauruhoe is a particularly good target for muon tomography, and it would be very desirable to try monitoring it this way if seismic or other information makes us think magma is rising within it.


Integrated density along each profile, i.e. sensitive to magma injection.


Timescale of Months.



Still a technique being developed, expect cheaper lighter sensing methods.

2012


Future Development of Geonet Seismic Analysis

Submission by Tony Hurst

Currently all the analysis of seismic data is based on standard seismology. This does not provide all the information that is wanted for volcano monitoring. Given our resources constraints, this requires automation as we don’t have staff time to manually go through the records. Initially, a number of the current analyses that are done as part of Volcano Development (i.e. pages on tarawera.gns.cri.nz) should move to become part of Geonet. We should be routinely checking the spectra of all events near the active volcanoes for classifying them, so that when we have Volcano Science meetings, we can easily see how unusual activity is.

Further out, I think we should be seeking to monitor changes in the conditions under the volcanoes by seeking to routinely calculate velocities and attenuation. This could include shear-wave splitting, coda-Q and noise correlation. Some of these techniques can be programmed to run automatically, but in some cases it requires better details on earthquake events, e.g. the automatic shear-wave splitting works best when S-picks are available, which is sometimes not the case.

2012


Submission title: Volcano source modelling

Researcher’s name: Art Jolly


Short period and broadband seismic data located within 20 km of the source area. Both types of sensors can be exploited to examine LP source processes, but VLP sources usually require broadband data.


Information about the behaviour of LP and VLP seismic sources can be determined (e.g. recognition and constraint of rapid volumetric changes and their geometry and orientation).

Basic information about the source position, geometry and moment history can be achieved with as few as 2-3 seismic stations (Nakano and Kumagai, 2005). Moderately constrained source geometries can be achieved with 5 stations along with the moment history, while full constraint of the source time function for all moment and single force components requires >15 stations (Bean et al, 2010).


• LP and VLP sources can be recognised in real time.

• Basic processing (e.g. particle motions, spectral analysis) can be achieved in hours to weeks.

• Source modelling from scratch requires about 2-3 months to acquire Greens functions and ~1 week for an inversion for common volumetric source geometries. Optional error analysis associated with the inversion requires 1 to2 months.

• If Greens functions have been pre-calculated within the relevant source volume, then the setup and inversion can be completed in 1 week, with error estimates in 1 to 2 months.

• The results can be used to inform hazards by identification of rapid volumetric changes beneath the volcanic edifice. Such information may be used to infer if processes are magmatic or non-magmatic in nature.

• Publication quality requires a 5 to 10 X multiplier for the above times for data consistency checks, adding value and innovation, writing up, etc.


Use of broadband seismometers on the volcanic edifice of composite cone volcanoes with a density of at least 2-3 stations within 20 km of the active vents (preferably less than 10 km)


The method may begin to incorporate new data types, e.g. tiltmeter data, acoustic data, etc. which will improve model constraints, In addition, computational improvements (improved software) will allow the inversions to be completed in hours rather than weeks.

2012


Submission title: Physical volcanology, hazard/risk assessments

Researcher’s name: Gill Jolly


Physical volcanology; volcanic hazard and risk


Phys volc: mostly only when an eruption occurs, but then the list increases markedly. Would include: radar, lidar, remote sensing (ash, thermal, visible), webcam IR, portable IR camera, topo.

Risk: the more types and increased volume the better, but emphasis would need to be on automatic datastreams to build robust data collection through an eruption


For both: better forecasting of hazards in near real-time.


Hazard assessments: using BET in theory, could change by the hour or day, depending on data rate.

Phys volc: during eruption, radar (at different scales – both Gert’s and a long range radar), ground-based lidar, IR cameras will give better eruption dynamics to inform MER, cloud height etc. Remote sensing: very wide range of applicability (see Joyce et al 2009). Regular surveys of topo during an eruption will provide up to data info for density current hazard modelling (eg Titan etc).


Having the gear available – bit difficult to justify given the lack of activity, but will be too late when it happens!


Cheaper and more portable instruments. Major changes in remote sensing for ash (both ground and satellite based) are expected in the next 5 years as a result of the Iceland experience.

2012


Submission title: Volcanic stratigraphy, geochronology and mapping

Researchers’ name: Graham Leonard, Dougal Townsend, Mike Rosenberg


Volcanic stratigraphy (the life history of volcanoes); volcanic geology; mapping; geochronology; physical volcanology


Stratigraphic logs of volcanic deposits (especially pyroclastics – ashfall and flows)

Maps of deposits (especially lavas and pyroclastic flows; and re-deposited lahars, debris flows and glacial moraine) based on topographic data, field outcrops and aerial photos

Petrology of samples (field descriptions, thin sections, geochemistry). Geochronology experiments on samples (14C, Argon-Argon and U-Th-Pb work on zircons).

Stratigraphy, petrology and geochemistry results are all iteratively fed into the mapping process improving the maps as data becomes available.


The style, size, timing and locations (maps) of past eruptions. Because human history is short in New Zealand, and quantitatively-monitored history is even shorter, we turn to pre-historic (and the few historic) eruption deposits. This submission covers the forensic study of what has happened at a volcano through its preserved deposits. We develop a full life history for the volcano. The recorded early history tends to be biased towards larger eruptions due to their preferential preservation, with increasing preservation of smaller more-frequent eruptions up through the sequence to young (Holocene) eruptions. Compensating for this bias we report and map an interpretation of the full likely history of eruptions from large to small.

The history and mapping of eruptions at a volcano are core datasets in (a) hazard and risk mapping and (b) forecasting of the character, duration and timing of future eruptions.


• Field mapping, sampling, hand specimen petrography, digital elevation and aerial photo interpretation can all be conducted at short notice with coarse results reported in near-real-time. More detail and accuracy is added with days to months of desk-based extra work.

• Petrology is usually conducted over weeks to months, but can be turned around in days if needed.

• Geochronology generally takes months to a year. 14C can be fast-tracked somewhat, but sample preparation, laboratory access and/or irradiation lead-times for Argon-Argon and U-Th-Pb work mean that months are required as a logistical minimum.

2012


• High quality holistic volcano histories through volcanic stratigraphy, geochronology and mapping are best developed as carefully planned multi-year research projects.

• These results are usually in the form of academic papers, bulletins and printed/digital maps.

• Because of the strong benefit in long-term research projects to carefully develop volcano histories such research is best conducted early before the results are needed for monitoring purposes. Then the results are published and readily available ahead of rapid forecasting needs.

• Volcanic hazard assessments, maps and response plans can also be derived from these datasets during ‘quiet times’ so that they are readily available during an event.


Priorities for sample collection and mapping could be regularly discussed with monitoring staff so that they are primed to notice new or unknown details in the field and report them to us for follow-up. Such information transfer already occurs to some extent.

FRST-funded QMAP and now MSI-funded National Geological Mapping - Volcano Maps projects have covered field mapping and petrology and will continue to for the next 5 years. Geochronology has been and will for the next 5 years be supported by MSI hazards platform volcanology funding. Beyond that the national geological mapping programme at least will move to other areas. At that time support of any further updates of geological maps may need consideration (e.g. to take up results of new trends and improvements in data).


Techniques for geomorphology mapping, geochronology and geochemistry are constantly improving, with new approaches emerging.

• LIDAR elevation data collection over volcanoes will likely continue to occur and significantly improve the quality of geomorphic mapping and its interpretation in the volcanic history.

• Improved sample preparation and mass-spectrometry methods for geochronology will mean more precision, revised accuracy and possibly improvements to sample usability over time (many samples are not suitable at present).

• Wholly-new geochronology techniques are likely to emerge that can be used to date currently un-datable deposits, or improve the accuracy or precision of existing dates.

• Trace element geochemistry continues to improve quickly. LA-ICPMS and dissolution-ICPMS are techniques available now that have only been applied to very few eruption deposits. Further application of these technologies and others that emerge will improve our ability to correlate deposits and understand how they relate to past and present magma systems.

• Maps and published eruption histories are iteratively updated as the above data are collected. During the 20th century such updates (especially to published maps) were commonly on a decadal or less frequent basis. With recent migration to digital mapping we will move towards more frequent updates in the order of years rather than decades.

2012


Submission title: Lahar monitoring at Ruapehu volcano

Researcher’s name: Vern Manville


Sensor arrays and power supply/telemetry systems located at strategic sites adjacent to predicted lahar flow paths, comprising elements of the following:

1. Vibration sensors: both acoustic flow monitors/geophones and broadband seismometers are suitable.

2. Non-contact (ultrasound or radar) stage gauges to measure flow height.

3. Sub-bed pore pressure transducers and earth pressure cells to measure flow depth, and potentially density and erosion/deposition rates.

4. Triggered camera systems (digital still, video, or webcam), with associated IR floodlighting.

5. pH and conductivity probes at downstream sites to measure water quality as a proxy for mixing of Crater Lake water with ambient river.

6. Pre- and post-event characterisation of channel geometries at monitoring sites using Terrestrial Laser Scanning.

7. Pressure-plate and impact counters on the leading edges of bridge piers and the OnTrack gauge to obtain data on dynamic lahar forces, sediment load and vertical concentration profile in active flows.


Data collected will yield information on the magnitude, sediment concentration, and downstream hydrodynamic evolution of lahars at Ruapehu triggered by a variety of mechanisms, including eruptions through Crater Lake, rain-triggered events, and lake break-outs. Two lahar-prone regions should be instrumented: (1) The Whangaehu valley; (2) The Whakapapa Skifield. Potential Whangaehu Valley sites should include at least 2 in the Gorge (i.e. Whangaehu Alpine Club hut, Tukino skifield, Round-the-mountain-track), plus additional sites further downstream (bund, OnTrack gauge, Tangiwai, Karioi, Colliers Bridge, Aranui, Kaungaroa). Location at previously utilised sites will permit continuity with historical records. Not all of these sites require the same level of instrumentation. Co-location with existing agency infrastructure should be investigated. Whakapapa sites should include the Waterfall valley and Far-West lahar paths.


• Lahars can be detected and their magnitude assessed in real time.

• Basic processing (e.g. discharge, volume) can be achieved in hours to weeks.

• More advanced processing (e.g. downstream hydrodynamic evolution) and error estimation can be calculated in weeks to months.

• The results can be used to inform hazards by identification of geophysical mass flows at

2012


Ruapehu. Such information can be used to develop improved hazard zonation.

• Publication quality requires a 5 to 10 X multiplier for the above times for data consistency checks, adding value and innovation, writing up, etc.


Previous efforts at lahar monitoring at Ruapehu have been based on ad hoc filed observations of active flows, or one-off solutions designed to meet the needs of a particular event (i.e. the March 2007 Crater lake break-out lahar). The frequency and diversity of lahars at Ruapehu (c. 5-10 year return period for Whangaehu valley lahar sequences) and (c. 20 years for Whakapapa Skifield lahars) demands installation of a dedicated, robust, and state-of-the-art lahar monitoring system.


Improvements in numerical modelling codes for the simulation of multiphase flows (e.g. lahars) will require improvements in calibration data. Lahar measuring techniques for further development include magnetic induction coils to measure total sediment flux and tiltmeters to measure ground deformation as a proxy for flow density.

2012


Submission title: Volcano degassing mechanism

Researcher’s name: Agnes Mazot


Volcanic fluids geochemistry


Gas emissions (CO2/SO2/H2S), seismic data and meteorological data (i.e.:rainfall, windspeed…)


Information about the influence of the meteorological parameters on the degassing process.

Relation with seismic data and short time variations in the degassing that are likely related to gas accumulation and buoyancy in the conduit and by atmospheric dispersion.


White Island:

• SO2 flux measured by Mini Doas acquired every day.

• Meteorological data acquired every day.

• The data are used to monitor the volcano and to see any change in the SO2 degassing and inform hazards.

• CO2/SO2/H2S flux data from gas measurement flight every month.

Ruapehu:

• Temperature of the crater lake and meteorological data every day.

• CO2/SO2/H2S flux data from gas measurement flight every month.


Use a continuous geochemical station on the volcanic edifice (Ruapehu) to have rapid information on the evolution of the degassing


The data acquisition maybe online and new data might be incorporated (acoustic, CO2/CO, Radon sensors…)

2012


Submission title: Borehole strain for NZ volcanoes.

Researcher’s name: Craig Miller


Borehole strain


Borehole strain data! Collocated with tilt and seismic preferably.


Data looking at changes in strain over time periods between tilt and gps data. Borehole strain was a part of the original GeoNet project but funding was transferred into other borehole technology such as seismic and tilt. It may be time to review the subject c.f. the operation of PBO strainmeters (ie does it work, is it worth doing, where would be the best targets in NZ?)

More than 1 station would probably be needed to change full understanding.


Real time data received but processing and analysis takes weeks-months.


By installing a borehole strainmeter!


Unsure. Need to check on the maturity of existing strainmeter technology and see how it has performed at other locations.

2012


Submission title: Infrasound array for NZ

Researcher’s name: Craig Miller


Infrasound


Infrasound array data from a proper multichannel, direction array system installed in a suitable quiet forest location.


Monitoring of explosions from volcanoes throughout New Zealand and potentially overseas. Infrasound can travel long distances in the correct atmospheric conditions. Incorporating infrasound measurements with seismic data can allow for better understanding of eruption processes, Infrasound observations complement seismic observations, allowing one to record the complete wavefield radiated by volcanoes.


Near real-time processing can be set up to provide rapid direction finding of the source of the signal. This could be used


By installing a true multichannel array with proper mechanical filtering of wind noise. Installation in a forest location would be best to reduce wind noise. Somewhere in the central North Island would cover most of NZ volcanoes.


Optical fibre interferometer instruments.

MEMs sensors

Improved signal processing?

2012


Submission title: Active system and groundwater interaction

Researcher’s name: Magali Moreau-Fournier


Groundwater


Chemical analyses (water and fumaroles), topographical datasets, geological information (maps, rock description, structural maps, bore logs), volcanic activity history (records, seismographs, historical activity record, volume and energy calculation), geophysical datasets (resistivity profiles, gravity data, spontaneous potential profiles), water budget information (Active lake temperatures, raingauge data, stream gauging data)


Characterization and delimitation of groundwater systems with respect to their connection to active volcanic areas, fluid circulation.

Groundwater mapping at depth (weeks to a couple of month if inversion is to be performed) and potential implication for active system

Water/Fluid budgets using lake temperatures for evapotranspiration in volcanic media.


Characterization and fluid circulation – weeks to months, can be used to set up or maintain or refine monitoring network

Water/Fluid budget – weeks to months, can be used to quantify fluid flow through an active system

Water prospection – several months between data acquisition and interpretation, may identify potential source for phreato-magmatism


Use of data loggers for physical and basic chemical monitoring to acquire time series.


Correlation between volcanic or tectonic event and groundwater chemistry/water levels.

For my areas of volcano science, making use of GeoNet data for research now or in future relies on the volcanoes actually erupting something. So unless someone else offers a physical volcanology perspective (that I might add to or comment on?), I won't be putting in a submission.

2012


When something is erupted I'd be interested in getting a handle on pre-eruption magma conditions (melt chemistry and volatiles) and conduit processes (vesiculation, fragmentation). Aside from that, the ash collection and rapid analysis (size, morphology, leachate chemistry, respirable size fractions and composition etc.) would probably be done with the VAT LAB consortium (us and Massey and Canterbury and others) as part of the whole event response. As far as I know there haven't been any major advances in the ash collection and analysis stuff in recent years, so there's nothing new to develop in terms of monitoring capability.

I'm open to suggestions, but haven't heard anything from any phys volc people within GNS or outside our group.

The so-called ash collection protocol has been dragging on and on without anything really coming together. In part I think that’s due to accord/discord between ourselves and various universities and various personalities. All about who was going to do the hard yards, leaving the “good science” to be cherry picked; who would be seen as experts making decisions and advising on what had happened and what was most likely to occur next. And who would be “responsible” for each volcano/volcanic centre. Anyway – all in the past.

Ash collection is all about doing the rounds putting containers out under the plume and retrieving and re-deploying as required. And it can mean collecting from suitable clean flat surfaces. Time consuming and labour intensive, but that’s what you have to do. There are good guidelines for ash collection and grainsize analysis, and suggestions for a bulk analysis procedure put together by Clare Horwell’s IVHHN group (in I:\volcanology and see http://www.ivhhn.org/guidelines.html). I helped to write an earlier version of these and I think they would work well for us in NZ. There would be some things to fine tune - like different analytical methods for detailed analysis, and what lab would do the analyses. Here, the rapid-response things we can do are leachate chemistry, particle sizing, XRD, and a first look at ash particle component types and morphology (by microscopy). I would step up and manage this, but I’d say the procedures and protocols are rusty and I don’t actually know how VATLAB and GNS fit together. Is GNS obliged to collect and process the ash through VATLAB? We want answers fast to disseminate to emergency managers and we don’t want duplication or analytical disagreement.

In terms of capability, we (GNS) are vulnerable simply because we would have to draft in labour at short notice and as far as I know, we have no plan in hand of how to do this or how to organise those people or feed and house them.

I terms of a new GeoNet volcano monitoring work plan, I’d advocate that we conduct a review to clarify the ash collection and analysis protocols and procedures. And for expenditure, I’d be asking to buy a compact digi-cam and microscope adapter (together <$1 k) so we can document morphology and component changes in ash during an eruption – for example progression from phreatic to phreatomagmatic to magmatic.

Michael Rosenberg 9th June 2011

http://www.ivhhn.org/guidelines.html

2012


Submission title: Application of BET_EF and BET_VH codes

Researchers’ names: Laura Sandri, Gill Jolly


Quantitative assessment of probabilistic hazard, especially related to volcanic phenomena


Essentially two broad categories of data: data from past eruptions (such as a catalogue of unrest episodes and of eruptions; maps of the extension of the deposits of past eruptions; estimates of the size or type of past eruptions) and data from monitoring activity, namely seismic data (countings; location and possibly depth; type of seismicity in terms of frequency and waveform like VT, LP, VLP), deformation (cumulated uplift, or strain, and rates) and geochemestry (e.g., fluxes, or presence of certain types of indicators).


We could be able to provide more sound eruption forecasting, i.e. to quantify (monthly, weekly, or daily) the probability of unrest, of eruption, and of what size. We could also quantify the associated volcanic hazard for relevant volcanic phenomena such as ballistics, lahars, pyroclastic flows, ash fall, lava flows.


Once all the input parameters of BET codes are set and installed, their usage takes few seconds. They could be incorporated into an operative routine feeding in them the data from monitoring, and providing as output the probabilities related to forecasting and hazard assessment.

More difficult is, however, the setting up, as we need to analyse the time series of different monitoring parameters to define which parameters to use and what threshold are indicative of anomaly.


If field collection of data from past eruptions or from monitoring is improved, then BET codes can be updated to entrain these potentially new pieces of information


If new models, or understanding, of the processes governing the trigger of unrest or of an eruption are available, they could be included in BET estimates to refine the output probabilities.

2012


Submission title: Monitoring stress and strain and their relation to volcanic processes. Determining the crustal and mantle structure of New Zealand.

Researchers’ names: Martha Savage, John Townend, Euan Smith and Tim Stern


Short period and broadband three-component seismic data located within 20 km of the source area. Higher density seismic stations on the volcanoes is helpful. Extra stations near the Erua and Waiouru swarm areas would help for monitoring purposes. Both types of sensors can be exploited to examine shear wave splitting and crustal structure, but broadband data can be more helpful for mantle structure.

If S arrivals are picked by a consistent set of rules, then we can automatically process the shear wave splitting data to determine if changes in anisotropy are occurring.


Crack distributions and orientations can be inferred from isotropic and anisotropic velocity. Changes in such distributions or orientations could reflect movement of fluids or stress changes at depth. Analysis of direct and converted phases from local and teleseismic earthquakes can help to determine structures, which might include sources of magma or geothermally altered areas.


• Shear wave splitting can be carried out automatically within minutes after a waveform is available with an S arrival time picked. Scatter in measurements usually means that on the order of ten earthquakes with magnitude greater than 3 are needed to get a good average: changes over months and possibly weeks could be monitored.

• Crustal structure studies require several years’ worth of data and usually provide an average structure over the time studied.


More stations are also always better, particularly over known sources of frequent activity such as the Waiouru and Erua swarms so that accurate locations can be obtained.


The biggest bottleneck now is the S arrival times, which are usually picked by hand. If a consistent automatic S wave picker could be obtained and tested, then automatic processing would be possible.

2012


Submission title: Data to understand Crater Lake processes

Researcher’s name: Brad Scott


Techniques to monitor volcanic crater lakes … Waimangu, Ruapehu, Raoul Island, White Island


Crater lake parameters; water level and temperature of the lake, overflow temperatures and volume.

Chemical parameters; ie Cl, Mg, pH etc

Gases.

The data is the technology to obtain the above.


If we can source and operate a suitable array of sensors, then we can set up remote monitoring of volcanic crater lakes and obtain more reliable time series data.

The crater lake calorimetry can be used to see changes in the enthalpy, at Ruapehu and Waimangu this has been shown to work for detecting changes in the hydrothermal systems and tectonic influences (eg the Edgecumbe earthquake caused changes at Waimangu)


Results can be obtained in a short time frame, 1-2 years.

The results can be used to inform hazards by identification of changes in the volcano-hydrothermal systems. Such information may be used to infer if processes are magmatic or non-magmatic in nature.

Constrain models.


Developing the technology will enable field data to be obtained, not just irregular sampling.


More portable chemical sensors and telemetry.

2012


Submission title: Acoustic arrays

Researcher’s name: Steven Sherburn


Recording volcanic eruptions using arrays of acoustic sensors.


Acoustic (airwave, infrasound) high sample rate time series data recorded at a multi-instrumented array close to a volcano.


During eruptive activity ....... Understand eruption processes and differing eruption styles by the acoustic signals they produce.


If data are telemetred signals can be processed in near real-time. Analysis of results will obviously take longer.

While results can inform hazards arrays usually operate at distances that preclude EDS-like hazard analysis.


Install and operate a multi-instrumented acoustic array!


I don't really know.

2012


Submission title: Stress mapping using earthquake focal mechanisms



Inverting earthquake focal mechanisms for stress orientations and possible time-varying stress.


Earthquake phase picks and first motions, and possibly locations (not necessary as can relocate, but quicker).


Stress orientations at seismogenic depths. Possible changes in stress orientations with time.


A single stress estimate requires a minimum of 20 focal mechanisms. Collection of sufficient data can take some years in areas of low or scattered seismicity.

I haven't been doing the actual stress inversions (someone else in the team has) so I'm not sure how long it takes. Interpretation could take months.

Code exists for estimating stress changes with time so this is quick to do, once the data are available.

Published work relates stress changes at volcanoes with intrusion episodes. This would be important for hazard assessment. Of course there has to be significant seismicity, of a sufficient magnitude, to provide data to construct focal mechanisms to start with.


Ensure seismographs are located in appropriate places to give the best focal distribution of first motions. Deployment telemetred portable instruments for moderate periods of time (one month to one year?) in locations that assist in getting focal mechanisms.


I don't really know.

2012


Submission title: Local earthquake tomography



Imaging sub-surface structure using seismic wave travel times from earthquakes located within and close to the area of interest.


Arrival time picks (P & S) and preliminary locations for earthquakes located within and close to the area of interest.


Models Vp and Vs distribution. These can be used for 'better' earthquake location. Understanding of structure in the modelled area.


This technique requires the accumulation of a significant amount of data. This will either take several years with the permanent network at background levels of seismic activity or can be achieved in a much shorter period if activity is greater, provided activity is widely distributed.

Analysis of a reasonable volume of data cannot normally be achieved in under several months. If additional phase picking is required then this will drastically extend the time required. Phase picking is a problem for current GeoNet data. The proportion of picks P:S is about 7:3, this is because only 'sufficient' S-phases are picked. This can limited the tomography.

Once a velocity model has been derived it can be used to relocate ongoing seismic activity to give, hopefully, a better estimate of event locations which better informs hazard evaluation.


With the fixed seismic network and variable location of seismicity in the TVZ we can usually sample enough of the model space if we collect data for a long enough period of time. If we want to improve our ability to image some poorly sampled part of our models and reduce the time taken to collect sufficient data for tomography we could deploy telemetred portable instruments for moderate periods of time (one month to one year?) in locations that assist our modelling.


Probably computational and the merging of different types of data?

2012


Submission title: Locating volcanic earthquakes



'Locating' volcanic earthquakes by use of amplitude data.


Near real-time seismic data for sites at a range of distances from the volcano.


Volcanic earthquakes and volcanic tremor cannot be located by traditional means as onset times are either difficult to measure sufficiently accurately or completely absent. Overseas work has shown that, when appropriately corrected, amplitude data can be used to determine a 'location' for these events. This can contribute to models to better understand the volcanic earthquake and tremor phenomena.


It might take (beyond playing around haven't really done it yet) some weeks to set up the appropriate correction factors. Once this is done basic 'location' could be done in a few minutes, interpretation, depending on the complexity of any modelling being attempted could take weeks.

Locations for volcanic seismicity will contribute to volcanic models and hazard assessment, particularly if depth variations are observed.


Ensure seismographs are located in appropriate places to give the necessary resolution. At this stage I'm not sure what that means but a suitable azimuthal and distance distribution seems a likely requirement. This may vary depending on the volcano and the source location & depth.


As I haven't yet attempted this work I don't really know.

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