HR: 1340h
AN: S13C-1457    [Abstracts]
TI: Epicenter Estimation Using Empirical Traveltime
AU: * Sheen, D
EM: dhsheen@kma.go.kr
AF: National Institute of Meteorological Institute, Korea Meteorological Administration, 45 Gisangcheong-gil, Dongjak-gu, Seoul, 151-760, Korea, Republic of
AU: Baag, C
EM: baagce@snu.ac.kr
AF: School of Earth and Environmental Sciences, Seoul National University, San 56-1, Sillim- dong, Gwanak-gu, Seoul, 151-742, Korea, Republic of
AU: Hwang, E
EM: hkawon@kma.go.kr
AF: Director General for Earthquake, Korea Meteorological Administration, 45 Gisangcheong- gil, Dongjak-gu, Seoul, 151-760, Korea, Republic of
AU: Jeon, Y
EM: ysjeon@kma.go.kr
AF: National Institute of Meteorological Institute, Korea Meteorological Administration, 45 Gisangcheong-gil, Dongjak-gu, Seoul, 151-760, Korea, Republic of
AB: A robust and efficient scheme to determine the epicenter in a local seismic network is proposed which uses an empirical traveltime from previous earthquakes, but does not rely on a seismic velocity structure of the region. An empirical traveltime is generated from the relationship between the epicentral distance and traveltime of the first arrival P phase. For a fast convergence of the method, two steps of the location scheme are used. A preliminary location is obtained by a geometrical method and the final epicentral location by a grid search algorithm. Empirical traveltimes are obtained from two different regions, southern California and South Korea, and the method is applied to both regions. Especially for the case of 138 earthquakes in southern California, occurring in 2007, the located epicenters in this study are so close to those from the bulletin that the average misfit is only 2.2 km. In both regions, the location misfits are especially small for earthquakes occurring within seismic networks. Large misfits are related with lack of traveltime information and velocity heterogeneity around the epicenter. As with other location algorithm, this method is also more accurate when the numbers of P arrivals are larger. In most cases of estimations in this study, however, only five or more arrivals can locate the epicenter accurately, which shows the potential for earthquake early warning and the usefulness in such regions where the velocity model is poorly known.
DE: 7200 SEISMOLOGY
DE: 7219 Seismic monitoring and test-ban treaty verification
DE: 7260 Theory
DE: 7290 Computational seismology
DE: 7299 General or miscellaneous
SC: Seismology [S]
MN: 2007 Fall Meeting