HR: 0800h
AN: S11A-1001    [Abstracts]
TI: 3D Geometric Structure of the Blind Fault for the 2003 Bam Earthquake_CSoutheast Iran_CInferred From the Aftershock Distribution: Existence of the Arg-e-Bam Fault Proposed
AU: Suzuki, S
EM: suzuki@geo.kyushu-u.ac.jp
AF: Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka, 812-8581 Japan
AU: * Nakamura, T
EM: nakamura@geo.kyushu-u.ac.jp
AF: Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka, 812-8581 Japan
AU: Sadeghi, H
EM: hsadeghi@science1.um.ac.ir
AF: Earthquake Research Center, Department of Geology, Faculty of Sciences, Ferdowsi University, Vakil-abad St., Mashhad, 91775-1436 Iran (Islamic Republic of)
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: Ito, Y
EM: yito@bosai.go.jp
AF: National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1, Tsukuba, 305-0006 Japan
AU: Hosseini, S
EM: hosseini@geo.kyushu-u.ac.jp
AF: Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka, 812-8581 Japan
AU: Jafar Gandomi, A
EM: gandomi@geo.kyushu-u.ac.jp
AF: Department of Earth and Planetary Sciences, Faculty of Sciences, Kyushu University, Hakozaki 6-10-1, Fukuoka, 812-8581 Japan
AU: Maleki, M
EM: Malekimeh@yahoo.com
AF: Natural Disaster Research Institute of Iran, Shabdiz Ave No.1, Tehran, 19395-4676 Iran (Islamic Republic of)
AU: Fatemi Aghda, S
EM: fatemi@saba.tmu.ac.ir
AF: Natural Disaster Research Institute of Iran, Shabdiz Ave No.1, Tehran, 19395-4676 Iran (Islamic Republic of)
AB: The 2003 Bam earthquake (Mw 6.5) occurred in the southeastern part of Iran on December 26, 2003. The mainshock caused severe damage, more than 26000 people died and tens of thousands of people injured, in the epicentral area. The relation of the mainshock with the heavily damaged area has not been well understood since nobody could find the source fault and even the hypocenter of the mainshok was not determined with a high accuracy. In order to find the source fault and study the relation to the damaged area, we installed 9 temporal seismic stations in and around the Bam city and conducted an aftershock observation during 1 month. We successfully recorded more than 18000 aftershock data and scanned onsets of P- and S-waves manually after several automatic data processings. The determined epicenters from these onset data are distributed linearly over about 20 km in parallel with a line 3.5 km west of the geological Bam fault and extend from the southern part of Bam city to the heavily damaged area in the eastern part of the city including the historical mud brick citadel "Arg-e-Bam". The hypocenters are distributed in a depth range from 0 km to 15 km and a seismic gap can be distinguished at a depth of less than 8 km. We named this hypocenter distribution "Arg-e-Bam fault" (Nakamura et al., 2004). We modeled 3D structure of the Arg-e-Bam fault based on the hypocenter distribution map. The estimated model resolves 6 fault segments that are consistent with a map of the damaged area. The branches of the fault with 3 segments are found in the NNW and NNE directions with different depth ranges in the northern part. The dip angle of segments is nearly 90 degrees from the surface, which does not extend to the Bam fault completely. Our estimated fault model shows a complicated deformation field especially in the northern parts and also indicates that the Arg-e-Bam fault is distinguished from the Bam fault.
UR: http://www.gaea.kyushu-u.ac.jp/research/iran2004/iran2004.html
DE: 7230 Seismicity and seismotectonics
DE: 8010 Fractures and faults
DE: 7200 SEISMOLOGY
DE: 7205 Continental crust (1242)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting