Moment tensor inversion of some aftershocks of the April 18, 1985 Luquan earthquake of Yunnan Province, China |
| |
Authors: | Jiangchuan Ni Yuntai Chen Ming Wang Mingxi Wu Jiayu Zhou Peide Wang and Francis T Wu |
| |
Institution: | (1) Institute of Geophysics, State Seismological Bureau, 100081 Beijing, China;(2) Department of Geological Sciences and Environmental Studies, State University of New York at Binghamton, 13901 Binghamton, New York, U. S. A. |
| |
Abstract: | Based on the three component accelerograms, recorded at near-field distance by a temporary seismic network consisting of digital
cassette tape recording accelerographs, the focal mechanisms of three aftershocks of the April 18, 1985, Luquan, Yunnan Province,
China, earthquake ofM
S=6.1, are calculated using seismic moment tensor inversion technique. The phases of direct P, S and converted SP waves in
the displacement seismograms, produced by twice integrations of the observed accelerograms, are identified via forward calculation
using Green’s functions for homogeneous semi-infinite elastic medium, and used in the inversion. The results of inversion
show that a better fit of synthetic to the observed seismograms of direct as well as converted phases can be achieved if appropriate
weighting functions are used in solving the over definite linear equations. While these aftershocks are of different magnitudes
(M
L=4.8, 3.2 and 3.5, respectively) and hypocentral locations, their focal mechanisms are very similar and consistent with that
of the main shock. This feature demonstrates the intrinsic correlation between the occurrence of aftershocks and the seismogenic
fault of main shock. Our experimentations show that using the near field accelerogram obtained from the digital seismic network
with appropriate azimuthal coverage on the focal sphere, with the aid of even simple medium model, not only the shear dislocation
source, but also the isotropic part and CLVD (compensated linear vector dipole) can be retrieved by the technique of moment
tensor inversion.
The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,13, 412–419, 1991.
This work is supported by the Chinese Joint Seismological Sciences Foundation and the Western Yunnan Earthquake Prediction
Test Site (WYEPTS), State Seismological Bureau. |
| |
Keywords: | Seismic moment tensor inversion earthquake mechanism Green’ s functions fault plane solution |
本文献已被 SpringerLink 等数据库收录! |
|