HR: 1340h
AN: T43A-1370    [Abstracts]
TI: Moho depth and two discontinuities variation in Taiwan from radial teleseismic receiver functions
AU: * Ton, C
EM: sei9203@eq.ccu.edu.tw
AF: Institude of Seismology, Natl. Chung-Cheng Univ., 168, University Rd., Min-Hsiung, Chiayi, 621 Taiwan
AU: Chen, C H
EM: seichen@eq.ccu.edu.tw
AF: Institude of Seismology, Natl. Chung-Cheng Univ., 168, University Rd., Min-Hsiung, Chiayi, 621 Taiwan
AB: In this study, we use data recorded by the stations of Broadband Array in Taiwan for Seismology (BATS) to investigate the depths of major discontinuities of the crust in Taiwan. From the differential times between direct P wave and converted Ps phase and several multiple phases on radial teleseismic receiver function, we determine the Moho depth and the Vp/Vs ratios at these stations. More importantly, we develop a method which can let us use more seismic phases to examine other discontinuities in the crust. Using the arrival times of some specific phases on radial teleseismic receiver function, except for Moho discontinuity, we found that there are two discontinuities ( denoted by discontinuity 1 and discontinuity 2 ) existing in the crust that beneath some of stations. The Moho depth in Taiwan varies from 22 to 39 km and Vp/Vs ratios varies from 1.64~1.87. The deepest Moho depth in Taiwan locates at the Central Mountain Range (CMR) and consistent with the result obtained from gravity survey. The discontinuity 1 and the discontinuity 2 exist clearly in the CMR, in the southern region and the northeastern region of Taiwan. These two discontinuities both become unapparent in the northern region (volcano region) and in the southeastern region (plate convergent area) of Taiwan. The depth of the discontinuity 1 varies from 4.5 to 11 km and while the depth of the discontinuity 2 varies from 12 to 22 km in our estimation. Based on these results, we imply that the discontinuity 1 and 2 are basement and the Conrad discontinuity respectively.
DE: 1219 Gravity anomalies and Earth structure (0920, 7205, 7240)
SC: Tectonophysics [T]
MN: Fall Meeting 2005