TRAVEL PATHS OF SURFACE WAVES ACROSS THE QINGHAI-XIZANG PLATEAU AND THE VELOCITY STRUCTURE
Author(s): CHEN HONG, HUANG ZHONG-XIAN
Pages: 270-280
Year: 1998 Issue: S1
Journal: Chinese Journal of Geophysics
Keyword: Qinghai-Xizang plateau; Travel paths of surface wave; Time-frequence polarization analysis; Interal heterogeneity; Ray tracing of surface wave.;
Abstract: A technique called time-frequency polarization analysis was applied to study thePOlarization direction of fundamental hove waves across different areas of Qinghai--Xizangplateau. The deviations of the incident direction which Love waves arrive’at the station indifferent peneds to the great circle paths were thus determined. The results show that Love waves propagating within the Qinghai--Xizap plateau didn’t deviate to the great circle paths LOve waves across the border zone of low velocity of Qinghai--Xizang plateau and western Chuandian area deviate obviously to the great circle paths. The velocity gradient in border zone of Qinghai--Xizang plateau and western Chuandian is large and affect the paths badly. Paths travel within the low velocity zone did not deviate obviously, the velocity gradient in Qinghai--Xizang plateau is smaller than in herder zone of the plateau. The position Of lowest velocity zone is about at the middle of Qinghai--Xizang plateau. The observed deviations of the Love wave paths are caused by the lateral heterogeneities of the velocity structure. Phase velocity grid model (4°× 4°) of different peneds is comPOSed using the results of 3--D velocity structure inversion. The deviations of Love waves across the phasevelocity model were calculated using ray tracing method. The results revealed that the phase velocity model produces deviations smaller but of the same sign to the Observed deviations.
Pages: 270-280
Year: 1998 Issue: S1
Journal: Chinese Journal of Geophysics
Keyword: Qinghai-Xizang plateau; Travel paths of surface wave; Time-frequence polarization analysis; Interal heterogeneity; Ray tracing of surface wave.;
Abstract: A technique called time-frequency polarization analysis was applied to study thePOlarization direction of fundamental hove waves across different areas of Qinghai--Xizangplateau. The deviations of the incident direction which Love waves arrive’at the station indifferent peneds to the great circle paths were thus determined. The results show that Love waves propagating within the Qinghai--Xizap plateau didn’t deviate to the great circle paths LOve waves across the border zone of low velocity of Qinghai--Xizang plateau and western Chuandian area deviate obviously to the great circle paths. The velocity gradient in border zone of Qinghai--Xizang plateau and western Chuandian is large and affect the paths badly. Paths travel within the low velocity zone did not deviate obviously, the velocity gradient in Qinghai--Xizang plateau is smaller than in herder zone of the plateau. The position Of lowest velocity zone is about at the middle of Qinghai--Xizang plateau. The observed deviations of the Love wave paths are caused by the lateral heterogeneities of the velocity structure. Phase velocity grid model (4°× 4°) of different peneds is comPOSed using the results of 3--D velocity structure inversion. The deviations of Love waves across the phasevelocity model were calculated using ray tracing method. The results revealed that the phase velocity model produces deviations smaller but of the same sign to the Observed deviations.
Related Articles