real time volcanic hazard evaluation during a volcanic crisis: bet_ef and the mesimex experiment

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Real time volcanic hazard evaluation during a Real time volcanic hazard evaluation during a volcanic crisis: BET_EF and the MESIMEX volcanic crisis: BET_EF and the MESIMEX

experimentexperiment

W. Marzocchi1, L. Sandri1, J. Selva1, G. Woo2

1- INGV-Bologna2- Risk Management Solution

Real time volcanic hazard evaluation during a Real time volcanic hazard evaluation during a volcanic crisis: BET_EF and the MESIMEX volcanic crisis: BET_EF and the MESIMEX

experimentexperiment

W. Marzocchi1, L. Sandri1, J. Selva1, G. Woo2

1- INGV-Bologna2- Risk Management Solution

Funded by INGV/DPC V4 and V3_4 Vesuvio projects

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OUTLINE of the presentationOUTLINE of the presentation

BET and Eruption ForecastingBET and Eruption ForecastingBET and Eruption ForecastingBET and Eruption Forecasting Why and how probabilities

Cost/benefit analysisCost/benefit analysisCost/benefit analysisCost/benefit analysis Basic idea about how to use probabilities

MESIMEX applicationMESIMEX applicationMESIMEX applicationMESIMEX application Checking how BET works

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what we are estimating here… what we are estimating here… what we are estimating here… what we are estimating here…

BET and Eruption ForecastingBET and Eruption ForecastingBET and Eruption ForecastingBET and Eruption Forecasting

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BET_EF PackageBET_EF PackageBET_EF PackageBET_EF PackageHazard procedure Target volcano

Event selection (Unrest + Magmatic Intrusion + Eruption+Vent all locs + SIZE=2+)

OUTPUT

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ABSOLUTE PROBABILITY CONDITIONAL PROBABILITY AT THE NODE

Selection done: (1) unrest -> (2) magmatic intrusion -> (3) eruption -> (4) location all -> (5) SIZE=4+

Probability that all the events in the selected path occur contemporaneously

Probability that the events at the selected node occur, given previous nodes


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BET_EF IS DISTRIBUTED FOR FREE BET_EF IS DISTRIBUTED FOR FREE A dedicated workshop will be held A dedicated workshop will be held

JULY 12, Room 16, Acad. of fine ARTS JULY 12, Room 16, Acad. of fine ARTS 17:30 - 20:30 (food and drinks available!)17:30 - 20:30 (food and drinks available!)

Marzocchi et al., JGR, 2004.Marzocchi et al., IAVCEI, Statistics in Volcanology, 2006.Marzocchi et al., Bull. Volc., 2007, in press.Marzocchi and Woo, in prep.

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Cost/Benefit analysisCost/Benefit analysisCost/Benefit analysisCost/Benefit analysis

Some useful considerations…Some useful considerations…

“Eruption forecasting” means to estimate probabilities

Typical requirement from end-users: YES or NOT (but the Nature seems not to much interested in playing deterministically)

How to interpret and to use probabilities? COMPARING THEM WITH MORE USUAL EVENTS

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Cost/Benefit analysisCost/Benefit analysisCost/Benefit analysisCost/Benefit analysis

P x L > CP x L > CP x L > CP x L > C

Let’s make the example of an evacuation (SIMPLIFIED!!!)L: cost of human lives lost due to an eruptionC: cost of an evacuationP: prob. of the deadly event (i.e., prob. of a pyroclastic flow)

If

the cost of human lives “probably” lost exceeds the cost of an evacuation. Therefore, the evacuation might be called when

P > C / LP > C / LP > C / LP > C / L

The evacuation will be called when the probability of The evacuation will be called when the probability of the deadly event will overcome a threshold defined a the deadly event will overcome a threshold defined a priori by Civil Protectionpriori by Civil Protection

The evacuation will be called when the probability of The evacuation will be called when the probability of the deadly event will overcome a threshold defined a the deadly event will overcome a threshold defined a priori by Civil Protectionpriori by Civil Protection

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Application to MESIMEXApplication to MESIMEX

You can download a report (in Italian) at the web siteYou can download a report (in Italian) at the web sitehttp://www.bo.ingv.it/~warnerhttp://www.bo.ingv.it/~warner

BET_EF code applied to MESIMEX. The code is developed in the INGV-DPC V4 project (leaded by W. Marzocchi & A. Zollo). The details are in Marzocchi et al., 2007; Bull. Volc., in press.

MESIMEX is an experiment (funded by European Community) simulating a possible future reactivation of Vesuvio, aiming to check the procedures for evacuation and managing the crisis. (The pre-eruptive scenario was develop by researchers independently from this study. NO FEEDBACK, BLIND TEST)

Monitoring parameters and thresholds are taken from Marzocchi et al., JGR, 2004.A revision of parameters and thresholds is under consideration in the project INGV-DPC V3_4 Vesuvius

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Application to MESIMEXApplication to MESIMEX 17 Oct. 2006, 08:00; Probability per month

Conditional Probability of specific size: Monitoring-independent!

VEI=3: 64%

VEI=4: 25%

VEI=5+: 11%

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CO2 flux = 10 Kg m-2 d-1

Other parameters inside the background


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Maximum magnitude in the last month = 4.2


N. events in the last month = 38


Seismic events localized out of crater


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Maximum magnitude in the last month= 4.2


N. events in the last month = 61 LP events in the last month = 2 T fumaroles = 100 0C

Presence of SO2 Localization of VT and LP


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Presence of SO2

Localization of VT and LP

5 10-5, d/dt = 5 10-5 d-1

3.6 Hz, ddt = -0.4 Hz d-1


If we agree with a cost/benefit ratio of 0.1, this is the momentIf we agree with a cost/benefit ratio of 0.1, this is the momentto evacuateto evacuate

If we agree with a cost/benefit ratio of 0.1, this is the momentIf we agree with a cost/benefit ratio of 0.1, this is the momentto evacuateto evacuate

X 0.35 = 0.22 > 0.1

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Presence of SO2


1 10-4, d/dt = 5 10-5 d-1

3.5 Hz, ddt = -0.5 Hz d-1


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Maximum magnitude in the last month= 4.2 N. events in the last month = 258 LP events in the last month = 131 T fumaroles = 110 0C

Presence of SO2


3 10-4, d/dt = 2 10-4 d-1

2.5 Hz, ddt = -1 Hz d-1 (tremor episodes) 0.3 (variations in hypocenters location)


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BET is a transparent tool to calculate and to visualize probabilities related to eruption forecasting/hazard assessment

BET performed well during MESIMEX. This does not mean that will be successful in forecasting the next eruption, but that it will represent satisfactorily and quantitatively the average opinion of researchers.

Cost/Benefit analysis is a very useful tool to interpret probabilities, i.e., it helps to translate probabilities into practical actions. It needs a collaborations between scientists (probability estimation) and decision makers (cost/benefit analysis)

The strategy adopted here has some clear advantages: it moves from subjective choices made during emergencies to objective choices defined transparently BEFORE the occurrence of a crises it is a “scientific tool” it creates a bridge between science and decision making

Points to take homePoints to take homePoints to take homePoints to take home

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““There are There are knownsknowns. There are things we know that we . There are things we know that we know. There are know. There are known unknownsknown unknowns - that is to say, - that is to say, there are things that we now know we don't know but there are things that we now know we don't know but there are also there are also unknown unknownsunknown unknowns. There are things we . There are things we do not know we don't know. So when we do the best do not know we don't know. So when we do the best we can and we pull all this information together, and we can and we pull all this information together, and we then say well that's basically what we see as the we then say well that's basically what we see as the situation, that is really only the known knowns and the situation, that is really only the known knowns and the known unknowns. And each year we discover a few known unknowns. And each year we discover a few more of those unknown unknowns.” more of those unknown unknowns.”

18 June 200318 June 2003

Defence Secretary Donald Rumsfeld Defence Secretary Donald Rumsfeld illuminates the volcanological problem :illuminates the volcanological problem :

real time volcanic hazard evaluation during a volcanic crisis: bet_ef and the mesimex experiment

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