HR: 1330h
AN: S32A-0840    [PDF]
TI: Modeling of receiver functions for laterally heterogeneous structures using a 2.5D FDM
AU: Ando, T
EM: andrew@geo.kyushu-u.ac.jp
AF: Dept. of Earth Planet. Sci., Kyushu Univ., Hakozaki 6-10-1, Fukuoka, 812-8581 Japan
AU: * Takenaka, H
EM: takenaka@geo.kyushu-u.ac.jp
AF: Dept. of Earth Planet. Sci., Kyushu Univ., Hakozaki 6-10-1, Fukuoka, 812-8581 Japan
AU: Okamoto, T
EM: taro@geo.titech.ac.jp
AF: Dept. of Earth Planet. Sci., Tokyo Inst. Tech., Ookayama 2-12-1, Meguro, Tokyo, 152-8551 Japan
AU: Murakoshi, T
EM: t.murakoshi@aist.go.jp
AF: AIST, Site 7, 1-1-1 Higashi, Tsukuba, 305-8567 Japan
AB: Receiver function analysis is one of the important and popular methods for study of the crust and upper mantle structures using teleseismic waveform data. In this analysis it is often necessary to calculate synthetic waveforms for the structure models. For this purpose horizontally layered structure models have been assumed, because the response of such a simple structure model to teleseismic P wave (plane wave) can be calculated easily and accurately by a semi-analytical method such as the propagator matrix method. However, for structures with strong lateral heterogeneity such as subdunction zones, it is often difficult to consider horizontally layered media for modeling the receiver functions observed above such complex structures. Full 3D modeling of seismic wave propagation is still computationally intensive. Recently, 2.5D methods for calculating 3D elastic wavefields in 2D varying media have been developed, which are an economical approach for calculating 3D wavefields, and require storage only slightly larger than those of the corresponding 2D calculations. Takenaka and Kennett (1996) proposed a 2.5D elastodynamic equation in the time domain for seismic wavefields due to obliquely incident plane waves in a 2D varying models. The azimuthal directions of the incident plane wave can be arbitrarily chosen from zero to 360 degrees. Nevertheless, the method requires only as small computation time as the 2D modeling. Takenaka and Okamoto (1997) used a finite-difference implementation of this 2.5D equation to simulate teleseismic seismograms at ocean-bottom stations for assessing the effect of sea-bottom topography. Here we apply this 2.5D finite- difference method (FDM) to modeling receiver functions for laterally heterogeneous structures. We demonstrate the efficiency of this approach with examples including a profile across a realistic model of subduction zone structure, and asses the effects of a subducting slab on the receiver function waveform observed at subduction zone.
DE: 7200 SEISMOLOGY
DE: 7203 Body wave propagation
DE: 7205 Continental crust (1242)
DE: 7218 Lithosphere and upper mantle
DE: 7260 Theory and modeling
SC: Seismology [S]
MN: 2003 Fall Meeting