HR: 0800h
AN: S51D-1031    [Abstracts]
TI: Pd attenuation and its application to earthquake early warning
AU: * Wu, Y
EM: drymwu@ntu.edu.tw
AF: National Taiwan University, Department of Geosciences No. 1, Sec. 4, Roosevelt Road, Taipei, 106 Taiwan
AU: Kanamori, H
EM: hiroo@gps.caltech.edu
AF: California Institute of Technology, Seismological Laboratory 1200 E. California Blvd., MS 252-21 , Pasadena, CA 91125 United States
AB: Pd is the peak amplitude of displacement during the first three seconds of P waves. Our previous studies in Taiwan (Wu and Kanamori, 2005a) and Southern California (Wu et al., 2005) showed that Pd correlates well with the peak ground-motion velocity (PGV) at the same location. Using Pd, we can predict the shaking intensity for earthquake early warning (EEW) purposes. We investigated the attenuation of Pd with the hypocentral distance (R) in southern California as a function of magnitude (M), and obtained the following relationship: log Pd(R)=-3.113+0.655M-1.384 log(R) +- 0.324 This relationship can be used in two ways. First, if we can locate the earthquake using the P arrival times at nearby stations, we can use this relationship to estimate the magnitude for regional EEW purposes. In our study, we can estimate the magnitude with a standard deviation of 0.23. Second, if the magnitude can be estimated from the average of the ground-motion period of the first three seconds of P waves (Kanamori, 2005; Wu and Kanamori, 2005b), then this relationship can be used to estimate the hypocentral distance. In our study, the ratio of the calculated to observed hypocentral distance varies from 0.52 to 1.72 around the average of about 1. This method is similar to that used in UrEDAS (Nakamura, 1988). References Kanamori, H. (2005). Real-time seismology and earthquake damage mitigation, Annual Review of Earth and Planetary Sciences 33, 5.1-5.20. Wu, Y. M. and H. Kanamori (2005a). Rapid assessment of damaging potential of earthquakes in Taiwan from the beginning of P Waves, Bull. Seism. Soc. Am. 95, 1181-1185. Wu, Y. M. and H. Kanamori (2005b). Experiment on an onsite early warning method for the Taiwan early warning system, Bull. Seism. Soc. Am. 95, 347-353. Wu, Y. M., H. Kanamori, R. M. Allen, and E. Hauksson (2005). An onsite earthquake early warning method for the Southern California Seismic Network, submitted to Bull. Seism. Soc. Am.. Nakamura, Y. (1988). On the urgent earthquake detection and alarm system (UrEDAS), Proceeding of 9th world conference on earthquake engineering, Tokyo-Kyoto, Japan.
DE: 7200 SEISMOLOGY
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: Fall Meeting 2005