nearest 1st annual meeting 25-26 october, 2007 - marralech
DESCRIPTION
Leader: INGV INGV Team: Laura Beranzoli , Davide Embriaco, Paolo Favali, Francesco Frugoni, Marco Lagalante, Nadia Lo Bue, Giuditta Marinaro, Stephen Monna, Claudio Viezzoli. NEAREST WP4. NEAREST 1st Annual Meeting 25-26 October, 2007 - Marralech. General on WP4 and WP Tasks - PowerPoint PPT PresentationTRANSCRIPT
NEAREST 1st Annual Meeting 25-26 October, 2007 - Marralech
NEAREST NEAREST
WP4WP4
Leader: INGV Leader: INGV INGV Team:INGV Team: Laura BeranzoliLaura Beranzoli, Davide Embriaco, Paolo Favali, , Davide Embriaco, Paolo Favali,
Francesco Frugoni, Marco Lagalante, Nadia Lo Bue, Giuditta Francesco Frugoni, Marco Lagalante, Nadia Lo Bue, Giuditta Marinaro, Stephen Monna, Claudio ViezzoliMarinaro, Stephen Monna, Claudio Viezzoli
Summary
• General on WP4 and WP Tasks
• Status of the activity
• Mission details
• Present status of the experiment
ObjectivesObjectives
The WP is aimed at carrying out geophysical and The WP is aimed at carrying out geophysical and oceanographic measurements on the seafloor and in the oceanographic measurements on the seafloor and in the water column in the nearby of near-shore tsunamigenic water column in the nearby of near-shore tsunamigenic sources for the sources for the identifications of tsunami signalsidentifications of tsunami signals. .
The seafloor and water column measurements will be The seafloor and water column measurements will be performed performed by means of a deep seafloor multiparameter by means of a deep seafloor multiparameter observatoryobservatory of GEOSTAR type, developed in previous of GEOSTAR type, developed in previous EC projects and will be transmitted to shore in EC projects and will be transmitted to shore in real-real-timetime (some essential parameters). (some essential parameters).
WP4 - Tsunami signal detection General
Task 4.1 Definition of sensor requirements and sensor selection; Task 4.1 Definition of sensor requirements and sensor selection; requirements of the detection software (e.g., detection requirements of the detection software (e.g., detection algorithm, triggering threshold, messages).algorithm, triggering threshold, messages).
Task 4.2 Design and development of modifications (e.g., sensor Task 4.2 Design and development of modifications (e.g., sensor supports of the frame); design and development of the supports of the frame); design and development of the software.software.
Task 4.3 Integration of new sensors/devices and new software in Task 4.3 Integration of new sensors/devices and new software in the seafloor observatory, tests of the functionality in the seafloor observatory, tests of the functionality in
laboratory.laboratory.
Task 4.4 Preparation planning and implementation of a long-term Task 4.4 Preparation planning and implementation of a long-term (about 1 year) mission; cruises for deployment and (about 1 year) mission; cruises for deployment and
recovery. recovery.
Task 4.5 Data back-up, quality checks, preparation of the data Task 4.5 Data back-up, quality checks, preparation of the data base to be integrated with other data; pre-analysis of base to be integrated with other data; pre-analysis of ‘parent’ ‘parent’ tsunami signals.tsunami signals.
General
ISMAR-BO.ISMAR-BO. FFCUL, CSIC FFCUL, CSIC marine site selection and marine site selection and characterisation for the pilot experimentcharacterisation for the pilot experimenton the basis of the on the basis of the knowledge of the areaknowledge of the area
ISMAR-BOISMAR-BO cruises responsiblecruises responsible
AWI, UGR, IM AWI, UGR, IM requirements of sensor sampling rates requirements of sensor sampling rates
TFH TFH MODUS for the pilot experiment MODUS for the pilot experiment (deployment/recovery) (deployment/recovery)
INGVINGV Seafloor observatory (GEOSTAR) Seafloor observatory (GEOSTAR)
ISMARBO
FFCUL CSIC AWI UBO INGV TFH UGR IM CNRST XISTOS
H H M M Leader H H M
Partners involved WP4 Partners involved WP4 General
D10D10 definition of sensors’, software definition of sensors’, software requirements for the deep-sea platformrequirements for the deep-sea platform
D11D11 detailed design for the integration of detailed design for the integration of new sensors and device in the deep-sea new sensors and device in the deep-sea platformplatform
D12D12 integration of new sensors, test of integration of new sensors, test of functionality of the deep-sea platformfunctionality of the deep-sea platform
D13D13 deployment procedure for the deep-sea deployment procedure for the deep-sea platformplatform
D14D14 deployment cruise of the deep-sea deployment cruise of the deep-sea platform and cruise reportplatform and cruise report
D15a recovery cruise of the deep-sea platform D15a recovery cruise of the deep-sea platform and data quality checksand data quality checks
D15bD15b cruise reportcruise report
WP4 DeliverablesWP4 Deliverables
m 4m 4
m 8m 8
m 11m 11
m 11m 11
m 12m 12
m 24m 24
m 24m 24
General
Experiment overview
Acoustictransmission
Satellite Link
GEOSTAR
MODUS
Task 4.1
Buoy
GEOSTAR Task 4.1
Tasks: • Scientific multiparametric data acquisition on relevant seismic source site
• Nearly real time warning event (seismic and sea level) identification and notification
The GEOSTAR seafloor observatory will be equipped with•sensor packages •acquisition, control units •data processing unit•local memory storage•acoustic communication system (towards sea surface buoy)
Sensor requirementsSensorSensor rate Acquisition
Triaxial broad band seismometer
100Hz - 3 comp. Continuous + (decimated) triggered events
Triaxial accelerometer 100Hz - 3 comp. Continuous + (decimated) triggered events
Hydrophone 100Hz Continuous
Pressure sensor 15sec Continuous
Structure accelerometer+Gyros
100Hz - 6 comp. Only on triggered events
Gravity meter 1Hz Continuous
CTD + Transmissometer
1smp/hour Continuous
ADCP 1profile/hour (40 layers/3 comp.)
Continuous
Currentmeter 5Hz Continuous
Task 4.1
SensorsSensor rate MODEL
Triaxial broad band seismometer
100Hz Guralp CMG-40
Triaxial accelerometer 100Hz Guralp CMG5-T
Hydrophone 100Hz OAS E-2PD
Pressure sensor 15secParoscientific 8CB4000-1
Accelerometer+Gyros (IMU) 100Hz Gladiator Technologies Landmark 10
Gravity meter 1Hz IFSI (INAF) Prototype #2
CTD + Transmissometer 1smp/hour SeaBird SBE 16 plus Wet Labs ECO-BBRTD 6000m
ADCP 1profile/hour RDI Workhorse 300 Khz
Currentmeter 5Hz Nobska MAVS-3
Task 4.2
Tsunami Detection Procedure
Trigger on Pressure and Seismic events
• Seismometer: trigger on local strong seismic event
• Pressure: detection of sea level anomalies (Tsunamis wave) details in the PART 2 of presentation (ISMAR)
Task 4.1
Buoy
The buoy is equipped with:• acoustic communication system (to the seafloor station)• satellite communication systems:
– to shore stations for data transmission (Globalstar) – buoy position tracking (ARGOS )
• meteo station
Task 4.1
Tasks:
• allows communication between GEOSTAR and shore stations (notification of possible tsunamis events)
• detects meteo data
Hydrophone
3D-ACM correntometro- da aggiornare
•Unique time reference for easy comparison of the signals
Paroscientific 8CB4000-1
Task 4.2
IMU
CMG-40T
Buoy layoutTask 4.2
Towards GEOSTAR
SatelIite
Real time Communication schemeTask 4.2
Acoustic link
Main station (INGV-Roma)
Service station
(backUp)
Secondary station
(ISMAR-BO)
Buoy
Satellite link
LAN - Internet link
Auxiliary stations
(mailboxes)
Messages/data availablesTipe of Tipe of messagesmessages
Available Available informationinformation
Direct Direct RecipientsRecipients
Periodic Sea level/meteo data/mission status
INGV-ISMAR
Event (seismic - pressure)
Time of event, pressure data (samples @15 sec)
All partners (nearly real time via e-mail)
End of mission
All sensor data NEAREST partners
Task 4.2
Mission scheduling 10 Aug -5 Sept.
r/v Urania (CNR-ISMAR)
GEOSTAR deployment in the selected site (B)
Buoy deadweight coordinates: GEOSTAR observatory coordinates: Lat. 36° 22.058’ N Lat. 36° 21,875’ N Lon. 09° 28.812’ W Lon 09° 28’.885 W Estimated depth: -3200 m Depth: -3207 m
Date: 25/08/2007Time: 21:14 GMT
Gulf of Cadiz Mission
The trigger algorithm used for the seismometer is run by the GURALP digitizer DM24. In this standard algorithm two data windows of different length are used to calculate a STA/LTA (Short Time Average over Long Term Average), where the signal amplitude averages are taken over two running windows:
The length in seconds of STW and LTW can be set by the operator.
An event is detected when
STA/LTA > RATIO
where RATIO is a number indicating a threshold value set by the operator.The smaller RATIO is, the more sensitive is the algorithm, i.e. it will trigger for smaller magnitude events.
STW- Short Term Window
LTW- Long Time Window
Another important parameter the operator can set is the
bandpass FILTER
In our case we want the algorithm to trigger only for events that have
M > Mx
where Mx, the lower bound magnitude, is defined by the following constrains:
•It should be big enough so that the algorithm doesn’t trigger too often, using up the observatory’s batteries too quickly
•It should be small enough too detect a “sufficient” number of events during the experiment so the triggering system can be tested
…….but this depends on the seismicity of the area….(and the background seismic noise level)……
So, to define the trigger parameters we consider……
NEARESTobservatory
Significant seismicity in the area of the Gulf of Cadiz (1960-present)Red circles are epicentres within 150 km of the 2007.02.12 ML5.9
From F. Carriho et al., Orfeus Newsletter, May 2007, vol. 7 No. 2
Distribution of recorded earthquakes over time
Magenta line shows the chosen lower bound magnitude (Mx) for triggering
From F. Carriho et al., Orfeus Newsletter, May 2007, vol. 7 No. 2
Then…
We decided that Magnitude=3 is the lower bound magnitude
We then decided to set the trigger parameters.
To avoid triggering for small magnitude local earthquakes (i.e. Ml2.5) the FILTER parameters are set to perform a
bandpass filter from 0.5 to 4.5 Hz
The RATIO parameter is set to 11 (STW to 1s, LTW to 50 s) based on the following:
•Trigger algorithm was run on deep sea broadband (Guralp 360 s) recordings from the Ionian Sea (SN-1 site) from events of varying amplitude. This dataset was chosen given the similar recording instruments and conditions.
•Trigger algorithm was run on on-land recordings from the Portuguese seismic network (IMP). Recordings show efficient propagation of seismic waves- good S/N ratio.
•General considerations on earthquake energy scaling with magnitude.
Following the observatory’s deposition unexpected triggering of the seismometer took place RATIO increased to 20 to make the algorithm less sensitive (and STW to 5 s).
Furthermore an OBS (obs07) was deployed close to the observatory’s site, for almost 2 days (from about 10:30 of 29/08 to about 9:30 of 31/08), to have a quick look at the seismic signal and infer something about signal recorded by the observatory’s sensor.After the deposition we found out that at the same time there was an active seismic experiment (shot energy is recorded above 5 Hz- shot frequency about every 20 s) and initially the frequent seismometer triggering was thought to be caused by the shots.
time (s)
velo
city
(m
/s)
Time scheduling
General
1 2 3 4 5 6 7 8 91
01
11
2
WP4
Task 4.1 Provisional
Actual x x x x x x x
Task 4.2 Provisional
Actual x x x x x x x
Task 4.3 Provisional
Actual x x
Task 4.4 Provisional
Actual x x x
Task 4.5 Provisional
Actual
Present status of the activities (m 12)
Evidence that the buoy answered interrogation from VEGA –
17 October 2007 15:58
Call to underwater modem attempted from VEGA
….connection with underwater modem from VEGA failed
Direct buoy link- Call on the buoy from Lisbon, positive response- 16 October 2007
Acoustic surface communication on-ship by the buoy site- configuration file correctly received by GEOSTAR-17 October 2007
Acoustic surface communication: Response to dacs status request command-
-17 October 2007
Acoustic communication with the observatory is attempted…….
17 October 2007
ATS-V-USS
(underwater) modem. Sending request (upload) of all values
in particular:
request of modem emission time parameter
Management of
……failure in the acoustic communication with the underwater modem- Time out signal received indicates no answer from GEOSTAR acoustic modem
An analysis with the trigger algorithm on obs07 signal, deployed during the active experiment:
there is no triggering with RATIO set to 20 (not even with RATIO set to 3).
So it seems unlikely (also given the filtering in the algorithm 0.5-4.5 Hz) that the shots started the initial triggering of the observatory sensor.
This was confirmed by a recent visit to the buoy where the operator did not find any trigger messages from the seismometer during the active experiment:
The only trigger found was of ‘pressure-type’, during an hour when a M=3.6 event at epicentral distance about 180 km fropm the observatory was recorded on land.
The absence of seismometer triggers prompted us to revert to the original RATIO=12 value.
The cause of the initial triggering is still unknown.
Deviations
• Anticipation of the cruise. Remedial action anticipation of Tasks (4.2, 4.3)
• Interference with the R/V Atalante seismic reflection experiment in the area: Remedial action: observatory software was properly reconfigured.
Atalante shot oceanographic cruise(info received from CNR-ISMAR)
Start End Shot occurrence
(s)
SignalFreq. (Hz)
Annotation
Date Time (GMT)
Date Time (GMT)
25 Aug. ‘07
01:45 28 Aug. ‘07
9:46 19.4 s (50 m)
10-50
29 Aug. ‘07
03:00 09/Sept. ‘07
06:00 29.2 s (75 m)
10-40 LON=6º 41.64468 ' W
LAT=36º 22.71906 ' N
(shot 1686-líne
MF22)
Deviations
• Acoustic communications malfunctioning: Immediately after the GEOSTAR deployment, a final check on the communication systems (acoustics and satellite) was performed both from the ship board and from the land station in Italy. A malfunctioning in the communication system, namely the acoustic modem, was discovered
Remedial action: the acoustic modem and the electronics of the buoy was removed and shipped to laboratory in order to set up again the communication chain. The system was restored and re-configured. On 17 October a new cruise has been planned in order to rebuild the communication on the buoy.
Deviations
• Inefficiency of the Globalstar satellite system coverage: by the early October, the Globalstar service provider (Elsacom) communicated that 4 satellites of the constellation failed.
Remedail Actions: the service provider was contacted in order to solicit the restoration of the constellation. The provider has then communicated that 2 satellites will be again operating from late October while other 2 satellites will be restored by the second half of November.
Last week….
• Buoy drift and ARGOS alarms emission to INGV (18 October)
• Extraordinary cruise for the buoy recovery
(18-22 October)
• Buoy mooring cut and mooring cable at sea
• Recovery of the buoy mooringRecovery of the buoy mooring
• Restoration of the buoy and deploymentRestoration of the buoy and deployment
• Integration of seismic data in the marine Integration of seismic data in the marine data-base of the OBS data (WP3 – data-base of the OBS data (WP3 – seismological monitoring) (task 4.5)seismological monitoring) (task 4.5)
Work for the next period