HR: 14:40h
AN: S23E-04    [Abstracts]
TI: Neural Network Methodology for Earthquake Early Warning - first applications
AU: * Wenzel, F
EM: friedemann.wenzel@gpi.uka.de
AF: Geophysical Institute Karlsruhe University, Hertzstr. 16, Karlsruhe, 76187, Germany
AU: Koehler, N
EM: nina.koehler@gpi.uka.de
AF: Geophysical Institute Karlsruhe University, Hertzstr. 16, Karlsruhe, 76187, Germany
AU: Cua, G
EM: georgia.cua@sed.ethz.ch
AF: Institute of Geophysics ETH Zurich, Hoenggerberg, Zurich, 8093, Switzerland
AU: Boese, M
EM: maren.boese@gpi.uka.de
AF: Geophysical Institute Karlsruhe University, Hertzstr. 16, Karlsruhe, 76187, Germany
AB: PreSEIS is a method for earthquake early warning for finite faults (Böse, 2006) that is based on Artificial Neural Networks (ANN's), which are used for the mapping of seismic observations onto likely source parameters, including the moment magnitude and the location of an earthquake. PreSEIS integrates all available information on ground shaking at different sensors in a seismic network and up-dates the estimates of seismic source parameters regularly with proceeding time. PreSEIS has been developed and tested with synthetic waveform data using the example of Istanbul, Turkey (Böse, 2006). We will present first results of the application of PreSEIS to real data from Southern California, recorded at stations from the Southern California Seismic Network. The dataset consists of 69 shallow local earthquakes with moment magnitudes ranging between 1.96 and 7.1. The data come from broadband (20 or 40 Hz) or high broadband (80 or 100 Hz), high gain channels (3-component). The Southern California dataset will allow a comparison of our results to those of the Virtual Seismologist (Cua, 2004). We used the envelopes of the waveforms defined by Cua (2004) as input for the ANN's. The envelopes were obtained by taking the maximum absolute amplitude value of the recorded ground motion time history over a 1-second time window. Due to the fact that not all of the considered stations have recorded each earthquake, the missing records were replaced by synthetic envelopes, calculated by envelope attenuation relationships developed by Cua (2004).
DE: 7212 Earthquake ground motions and engineering seismology
DE: 7215 Earthquake source observations (1240)
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Seismology [S]
MN: 2007 Fall Meeting