HR: 1340h
AN: S53B-0194    [Abstracts]
TI: Crustal Structure in Southern Korea From Joint Analysis of Teleseismic Receiver Functions and Surface Wave Dispersion
AU: * Chang, S
EM: jaang@seismic.snu.ac.kr
AF: Seoul National University, San 56-1 Shillim 9-dong Gwanak-gu, Seoul, 151747 Korea, Republic of
AU: Baag, C
EM: baagce@snu.ac.kr
AF: Seoul National University, San 56-1 Shillim 9-dong Gwanak-gu, Seoul, 151747 Korea, Republic of
AB: We estimated crustal structures at eighteen broadband stations in southern Korea by combining receiver functions and surface wave dispersion with the genetic algorithm (GA). The trend of the Moho depths estimated from the GA inversion generally coincides with the topography of the surface, ranging from 26 km to 36 km in inland. However, the Moho depth distribution does not agree with the topography in the region around the Chugaryeong Fault located approximately in NNE-SSW direction in the central area of the Korean peninsula. The shallow Moho depth under this region may be related to magmatic rift and consequential crustal thinning processes along the fault caused by an extensional tectonic movement. Another discrepancy is found in the Gyeongsang Basin, which was formed by the sedimentary deposits accumulated during Cretaceous extension caused by retroarc environment. The thick crust may be caused by both the maturity of basin and underplating of magma materials after the closure of the basin. The average crustal velocity is variable from 6.02 km/sec to 6.51 km/sec over southern Korea. This indicates that crustal structures in southern Korea involve diverse velocity profiles, changing rapidly with distance. It is also a remarkable phenomenon that an obvious discontinuity of the velocity is observed at 8-10 km depths under several stations.
DE: 7260 Theory and modeling
DE: 7203 Body wave propagation
DE: 7205 Continental crust (1242)
DE: 7218 Lithosphere and upper mantle
SC: Seismology [S]
MN: 2004 AGU Fall Meeting