Open AccessInterferometric synthetic aperture radar observations of the 1994 Double Spring Flat, Nevada, earthquake ( M 5.9): Main shock accompanied by triggered slip on a conjugate fault
Author(s) -
Amelung Falk,
Bell John W.
Publication year - 2003
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jb001953
Subject(s) - geology , seismology , aftershock , slip (aerodynamics) , induced seismicity , fault plane , fault (geology) , basin and range topography , geodesy , tectonics , physics , thermodynamics
The 1994 Double Spring Flat (DSF) earthquake ( M 5.9) was the largest earthquake to strike Nevada in more than 30 years. It occurred in the Sierra Nevada‐Basin and Range Transition Zone within a step‐over region between two major normal faults. Descending and ascending ERS interferograms show a maximum range change of 8.5 cm which is the coseismic ground displacement associated with this normal, oblique‐slip, moderate‐sized earthquake. Elastic inverse modeling and surface displacements across coseismic ground cracks suggest that two different event sources could account for the observed deformation. The first source was the main shock with right‐oblique slip on the north‐northwest striking DSF fault. The second source was normal faulting on a shallow, north‐northeast striking, elongated plane (conjugate to the DSF fault). These two sources are consistent with the pattern of postevent seismicity, and we suggest that the second source represents seismic and aseismic slip triggered by the main shock. Calculations of changes in Coulomb failure stress show that the main shock encouraged normal slip on this plane.