HR: 1340h
AN: S13B-0206    [Abstracts]
TI: Rupture Velocity of the 2002 East China Deep Earthquake (Mw 7.3)
AU: * Park, S
EM: suncheon@eqh.dpri.kyoto-u.ac.jp
AF: Disaster Prevention Research Institute, Kyoto University,Gokasho, Uji, Kyoto, 611-0011 Japan
AU: Mori, J
EM: mori@eqh.dpri.kyoto-u.ac.jp
AF: Disaster Prevention Research Institute, Kyoto University,Gokasho, Uji, Kyoto, 611-0011 Japan
AB: Recent studies on deep earthquake have suggested that deep earthquake source properties vary with the temperature of the subducting plate. Earthquakes in cold slabs have high aftershock activity, high rupture velocity and high seismic efficiency, while events in warm slabs have low aftershock activity, low rupture velocity and low seismic efficiency. These contrasts of the source properties seem to be distinguishable in very low (~2000 km, warm slab) and very high (~10000 km, cold slab) thermal parameters (The thermal parameter is the product of the velocity of subduction and the age of the plate). The thermal parameter of the Pacific slab (~6000 km) is in the middle of the two representative values of warm and cold slabs, and the source properties of deep earthquakes do not show clear characteristics. As first step toward understanding the source properties of deep earthquakes in the Pacific slab, we investigated the rupture velocity of the 2002 East China deep earthquake which occurred at about 560 km depth on June 28, 2002. The moment magnitude (Mw) is 7.3. This earthquake shows a strong directivity from northeast to southwest. Using waveforms of F-net stations of NIED (National Research Institute for Earth Science and Disaster Prevention), Japan with azimuths of 86 ~ 188°, the time differences between the P arrival and a large later arrival were measured. Then we calculated the relative azimuth, dip and distance to the hypocenter. The relative azimuth, dip and distance were 248°, -18° (or 18°) and 16.3 km. With these results, the rupture velocity was obtained as 1.6 km/s. This result of rupture velocity will be a good constrain for investigating the source process and the source properties of this deep earthquake.
DE: 7200 SEISMOLOGY
DE: 7215 Earthquake source observations (1240)
SC: Seismology [S]
MN: Fall Meeting 2005