HR: 14:20h
AN: S53A-04 INVITED     [Abstracts]
TI: Imaging S wave reflectors in and around hypocentral area of the 2004 Niigata-ken Chuetsu Earthquake (M6.8)
AU: * Matsumoto, S
EM: matumoto@sevo.kyushu-u.ac.jp
AF: Institute of Seismology and Volcanology, Faculty of Sciences, Kyushu University, Shin-yama 2-5643-29, Shimabara, 855-0843 Japan
AU: Iio, Y
EM: iio@rcep.dpri.kyoto-u.ac.jp
AF: Research Center for Earthquake Prediction, Disaster Prevention Research Institute, Kyoto University , Gokasho, Uji, 611-0011 Japan
AU: Matsushima, T
EM: mat@sevo.kyushu-u.ac.jp
AF: Institute of Seismology and Volcanology, Faculty of Sciences, Kyushu University, Shin-yama 2-5643-29, Shimabara, 855-0843 Japan
AU: Uehira, K
EM: uehira@sevo.kyushu-u.ac.jp
AF: Institute of Seismology and Volcanology, Faculty of Sciences, Kyushu University, Shin-yama 2-5643-29, Shimabara, 855-0843 Japan
AU: Shibutani, T
EM: shibutan@rcep.dpri.kyoto-u.ac.jp
AF: Research Center for Earthquake Prediction, Disaster Prevention Research Institute, Kyoto University , Gokasho, Uji, 611-0011 Japan
AB: We studied about a distribution of S wave reflectors in and around hypocentral area of the 2004 Niigata-ken Chuetsu Earthquake (M6.9). The earthquake accompanied with several large after shocks greater than M6. Moreover, the aftershocks were not only located on the fault plane of the main shock, but also on a conjugate fault and that parallel to the main shock one. In order to discuss the relationship between such a complex activity and the crustal heterogeneities, we analyzed seismograms observed at seismic stations in this region. Normal moveout processing (NMO) was applied to the data of the aftershock. From the NMO sections for every stations, many S wave reflector could be found. Especially, relatively strong reflectors for S waves exist in the lower crust at about a depth range of 20 - 25km in the middle part of aftershock area. In addition, reflectors were found beneath the fault planes of the main shock and largest aftershock. This suggests a possibility of the correlation of the crustal heterogeneities to the earthquake occurrence.
DE: 7200 SEISMOLOGY
DE: 7203 Body wave propagation
SC: Seismology [S]
MN: 2005 Joint Assembly