HR: 0800h
AN: S11C-0715    [Abstracts]
TI: Using the ETAS model for catalog declustering and seismic background assessment.
AU: * Console, R
EM: console@ingv.it
AF: Istituto Nazionale di Geofisica e Vulcanologia, Via Vigna Murata 605, Rome, RM 00143, Italy
AU: Catalli, F
AF: Istituto Nazionale di Geofisica e Vulcanologia, Via Vigna Murata 605, Rome, RM 00143, Italy
AB: The concept of background seismicity is strictly related to the identification of spontaneous and triggered earthquakes. The definition of foreshocks, main shocks and aftershocks is currently based on procedures depending on parameters whose values are notoriously assumed by subjective criteria. We propose a method for recognizing the background and the induced seismicity in statistical way. In fact, rather than aiming to a crude distinction of the events in these two categories, we prefer to assign to each of them a probability of being independent or triggered. This probability comes from an algorithm based on the ETAS model. A certain degree of subjectivity is still present in this procedure, but it is limited by the possibility of adjusting the free parameters of the algorithm by rigorous statistical criteria such as that of the maximum likelihood. The robustness of the method can be shown by comparing the results obtained selecting different time windows from a given catalog. In the application of the method to the seismicity of California, we analyze how the determination of some of the free parameters of the algorithm affects the results. Finally, we show how our statistical declustering algorithm may be used for mapping the background seismicity.
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Seismology [S]
MN: 2007 Fall Meeting