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Journal: |
Geophysical Journal International 2019 No.1
clicks:166 |
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Title:
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Author:
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Jing Hu |
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Adress: |
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Abstract:
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Based on seismic array, the conventional frequency–wavenumber method, or
the FK method, is generally used to determine the backazimuth and slowness
parameters for the plane wave arriving at the seismic array. However, at low
frequencies the FK method results in low-resolution estimation of both
parameters. To overcome this issue, we have developed a new seismic array
analysis method based on sparsity-constrained (SC) inversion to better determine
the backazimuth and slowness parameters. The SC method takes advantage of the
sparsity of the incoming wave front in the domain of slowness and backazimuth.
We have tested the proposed SC method using synthetic data calculated for
Shanghai Earthquake Agency Array (SEAA) from one single source and two sources,
respectively. Compared to the FK method, the proposed SC method has a much
higher resolution in estimating the backazimuth and slowness parameters.
Furthermore, the SC method can more easily separate multiple sources and
estimate the two parameters. We also compare the proposed SC method with
another advanced seismic array analysis method CLEAN-PSF, which can find the
position and strength of point sources. Overall, our proposed SC method
performs better than or at least at the comparable level as the CLEAN-PSF
method. We further demonstrate the effectiveness of the new method on the 2008
Mw 8.0 Wenchuan earthquake data recorded on the SEAA. The deviation between
theoretic backazimuth and optimal solution is approximately 4°, indicating the
capability of the proposed SC method for reliably estimating the backazimuth of
teleseismic event based on a seismic array. |
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