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Estimation of an earthquake focal mechanism from a satellite radar interferogram: Application to the December 4, 1992 Landers aftershock
Author(s) -
Feigl Kurt L.,
Sergent Arnaud,
Jacq Dominique
Publication year - 1995
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/94gl03212
Subject(s) - geology , focal mechanism , geodesy , seismology , hypocenter , interferometric synthetic aperture radar , aftershock , thrust fault , rake , synthetic aperture radar , fault (geology) , induced seismicity , remote sensing , geomorphology
Using the interferometric fringes generated by the phase difference between a pair of synthetic‐aperture radar (SAR) images acquired by the ERS‐1 satellite, we estimate the focal mechanism of a small, shallow thrust earthquake. The inversion procedure is an iterative, linearized least‐squares algorithm based on a standard elastic dislocation formulation for coseismic displacements. Our preferred estimate is a thrust focal mechanism with its hypocenter at (N34.35° ± 0.4 km, W116.91° ± 0.2 km, 2.6 ± 0.3 km depth) on a plane dipping southward beneath the San Bernardino Mountains, with a moment magnitude (M w ) of 5.4. The strike, dip, and rake are N106°E ± 7°, 28° ± 4°, and 93° ± 4°, respectively on a fault 3.1 ± 0.5 km wide and 2.9 ± 0.4 km long. The precision of these estimates is competitive with seismological determinations.