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Titel |
Wave-equation-based travel-time seismic tomography – Part 2: Application to the 1992 Landers earthquake (Mw 7.3) area |
VerfasserIn |
P. Tong, D. Zhao, D. Yang, X. Yang, J. Chen, Q. Liu |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1869-9510
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Digitales Dokument |
URL |
Erschienen |
In: Solid Earth ; 5, no. 2 ; Nr. 5, no. 2 (2014-11-26), S.1169-1188 |
Datensatznummer |
250115351
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Publikation (Nr.) |
copernicus.org/se-5-1169-2014.pdf |
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Zusammenfassung |
High-resolution 3-D P and S wave crustal velocity
and Poisson's ratio models of the 1992 Landers earthquake (Mw 7.3)
area are determined iteratively by a wave-equation-based travel-time
seismic tomography (WETST) technique. The details of data selection, synthetic arrival-time
determination, and trade-off analysis of damping and smoothing
parameters are presented to show the performance of this new
tomographic inversion method. A total of 78 523 P wave and
46 999 S wave high-quality arrival-time data from 2041
local earthquakes recorded by 275 stations during the period of
1992–2013 are used to obtain the final tomographic models, which cost
around 10 000 CPU hours. Checkerboard resolution tests are
conducted to verify the reliability of inversion results for the
chosen seismic data and the wave-equation-based travel-time seismic
tomography method. Significant structural heterogeneities are revealed
in the crust of the 1992 Landers earthquake area which may be closely
related to the local seismic activities. Strong variations of velocity
and Poisson's ratio exist in the source regions of the Landers and
three other nearby strong earthquakes. Most seismicity occurs in
areas with high-velocity and low Poisson's ratio, which may be
associated with the seismogenic layer. Pronounced low-velocity
anomalies revealed in the lower crust along the Elsinore, the San
Jacinto, and the San Andreas faults may reflect the existence of fluids
in the lower crust. The recovery of these strong heterogeneous
structures is facilitated by the use of full wave equation solvers
and WETST and verifies their ability in generating high-resolution
tomographic models. |
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