HR: 09:15h
AN: S31A-06    [PDF]
TI: Coulomb Stress Modelling as a Practical Tool in Real-time Aftershock Hazard Assessment: the Example of the PRESAP Blind Test
AU: * Scotti, O
EM: oona.scotti@irsn.fr
AF: Institut de Radioprotection et Surete Nucleaire, BP 17, FONTENAY-AUX-ROSES C, F-92265 France
AU: Steacy, S
AF: UNIVERSITY OF ULSTER, Geophysics Group, School of Environmental Studies, Coleraine, BT52 1SA United Kingdom
AU: Cocco, M
AF: Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, ROMA, I-00143 Italy
AU: Zahradnik, J
AF: Department of Geophysics, Faculty of Mathematics and Physics, Charles University, KG MFF UK, V Holesovickach 2, Praha 8, 180 00 Czech Republic
AU: Mc Closkey, J
AF: UNIVERSITY OF ULSTER, Geophysics Group, School of Environmental Studies, Coleraine, BT52 1SA United Kingdom
AB: We present results of a pseudo real-time scenario that was performed in the framework of the PRESAP (Practical, Real-Time Estimation of Spatial Aftershock Probabilities) project. The aim of the PRESAP project is to assess the feasibility of using Coulomb stress modelling to make real time estimations of the likely spatial distribution of off-fault aftershocks following a large event. As part of this project, the scenario was designed to test the practicality of making such assessments in real time. Data from a recorded earthquake, not studied in the PRESAP project and not known in advance by the participants, were made available in the time ordered sequence and in the raw form as it would have arrived. The test was managed through a website where data and results were continually posted by the participants located all over Europe. Results show that CST may indeed provide useful guidance in the identification of potential fault sources. The location of aftershocks in association with a-priori knowledge of the kinematics of potentially active faults played a key role in decision-making. In the case where the number of available aftershocks would have been sufficient, statistical tests could have also been used. The success of the blind-test was in part due to the "simple" vertical strike-slip faulting tectonics of the region concerned but in particular due to the good knowledge of the active faults. In regions where the tectonics is more complex (e.g. Athens 1999 earthquake, Umbria-Marche 1997 sequence), the exercise may not be so straightforward. Nevertheless, real-time estimates may be improved by pre-computing a range of potential fault scenarios for both Coulomb stress perturbations and expected ground motions that are likely to affect the critical sites of interest.
UR: http://www.errigal.ulst.ac.uk/
DE: 7209 Earthquake dynamics and mechanics
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2003 Fall Meeting