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

Real time volcanic hazard evaluation during a volcanic crisis: BET_EF and the MESIMEX experiment W. Marzocchi 1 , L. Sandri 1 , J. Selva 1 , G. Woo 2 1- INGV-Bologna 2- Risk Management Solution. Funded by INGV/DPC V4 and V3_4 Vesuvio projects. BET and Eruption Forecasting.

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

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  1. Real time volcanic hazard evaluation during a volcanic crisis: BET_EF and the MESIMEX experiment W. Marzocchi1, L. Sandri1, J. Selva1, G. Woo2 1- INGV-Bologna 2- Risk Management Solution Funded by INGV/DPC V4 and V3_4 Vesuvio projects

  2. BET and Eruption Forecasting Why and how probabilities Cost/benefit analysis Basic idea about how to use probabilities MESIMEX application Checking how BET works OUTLINE of the presentation

  3. BET and Eruption Forecasting what we are estimating here…

  4. BET and Eruption Forecasting Hazard procedure Target volcano OUTPUT Event selection (Unrest + Magmatic Intrusion + Eruption+Vent all locs + SIZE=2+) BET_EF Package

  5. BET and Eruption Forecasting Selection done: (1) unrest -> (2) magmatic intrusion -> (3) eruption -> (4) location all -> (5) SIZE=4+ ABSOLUTE PROBABILITY CONDITIONAL PROBABILITY AT THE NODE Probability that all the events in the selected path occur contemporaneously Probability that the events at the selected node occur, given previous nodes

  6. BET_EF IS DISTRIBUTED FOR FREE A dedicated workshop will be held JULY 12, Room 16, Acad. of fine ARTS 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.

  7. Cost/Benefit analysis • 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

  8. Cost/Benefit analysis Let’s make the example of an evacuation (SIMPLIFIED!!!) L: cost of human lives lost due to an eruption C: cost of an evacuation P: prob. of the deadly event (i.e., prob. of a pyroclastic flow) If P x L > C the cost of human lives “probably” lost exceeds the cost of an evacuation. Therefore, the evacuation might be called when P > C / L The evacuation will be called when the probability of the deadly event will overcome a threshold defined a priori by Civil Protection

  9. Application to MESIMEX • 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 You can download a report (in Italian) at the web site http://www.bo.ingv.it/~warner

  10. Application 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%

  11. Application to MESIMEX 17 Oct. 2006, 09:00; Probability per month • CO2 flux = 10 Kg m-2 d-1 • Other parameters inside the background

  12. Application to MESIMEX 18 Oct. 2006, 07:00; Probability per month • Maximum magnitude in the last month = 4.2 • N. events in the last month = 38 • CO2 flux = 10 Kg m-2 d-1 • Seismic events localized out of crater • Other parameters inside the background

  13. Application to MESIMEX 19 Oct. 2006, 09:00; Probability per month • 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 • CO2 flux = 20 Kg m-2 d-1 • Presence of SO2 • Localization of VT and LP • Other parameters inside the background

  14. Application to MESIMEX 19 Oct. 2006, 18:00; Probability per month If we agree with a cost/benefit ratio of 0.1, this is the moment to evacuate X 0.35 = 0.22 > 0.1 • Maximum magnitude in the last month= 4.2 • N. events in the last month = 104 • LP events in the last month = 26 • T fumaroles = 110 0C • CO2 flux = 30 Kg m-2 d-1 • Presence of SO2 • 5 10-5, d/dt = 5 10-5 d-1 • <3.6 Hz, d<dt = -0.4 Hz d-1 • Localization of VT and LP • Other parameters inside the background

  15. Application to MESIMEX 20 Oct. 2006, 15:00; Probability per month • Maximum magnitude in the last month= 4.2 • N. events in the last month = 183 • LP events in the last month = 61 • T fumaroles = 110 0C • CO2 flux = 300 Kg m-2 d-1 • Presence of SO2 • 1 10-4, d/dt = 5 10-5 d-1 • <3.5 Hz, d<dt = -0.5 Hz d-1 • Localization of VT and LP • Other parameters inside the background

  16. Application to MESIMEX 21 Oct. 2006, 17:00; Probability per month • 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 • CO2 flux = 400 Kg m-2 d-1 • Presence of SO2 • 3 10-4, d/dt = 2 10-4 d-1 • <2.5 Hz, d<dt = -1 Hz d-1 (tremor episodes) • 0.3 (variations in hypocenters location) • Localization of VT and LP

  17. Points to take home • 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

  18. Defence Secretary Donald Rumsfeld illuminates the volcanological problem : “There are knowns. There are things we know that we know. There are known unknowns - that is to say, there are things that we now know we don't know but there are also unknown unknowns. There are things we do not know we don't know. So when we do the best we can and we pull all this information together, and we then say well that's basically what we see as the situation, that is really only the known knowns and the known unknowns. And each year we discover a few more of those unknown unknowns.” 18 June 2003

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