Kinematic source parameters determined by time-dependent moment-tensor inversion and an analysis of teleseismic first motions

Journal Article · Mon Jan 01 00:00:00 EST 1990 · United States Geological Survey, Professional Paper; (USA)

OSTI ID:5471339

Sipkin, S A; Needham, R E

A waveform-inversion technique was applied to the digitally recorded long-period P-waveform data from the Global Digital Seismograph Network for the May 2 earthquake. The solution was constrained to be purely deviatoric but not to be a double couple. The source depth was determined by finding a trial depth that minimized the misfit to the data. By allowing the elements of the moment tensor to be independent, arbitrary functions of time, a gross estimate of the source-time history of the rupture process was obtained. A moderately well constrained fault-plane solution was also obtained by fitting the available long-and short-period teleseismic first-motion data. The strike, dip, and rake of the first-motion solution are 307{degree}, 70{degree}, and 90{degree}, respectively. This solution is very close to the best double-couple of the step-function moment-tensor solution of 303{degree}, 72{degree}, and 97{degree}. The best fitting depth is 11 km and the scalar moment is 4.7 {times} 10{sup 25} dyne-cm. The non-double-couple part of the moment tensor is 28%. This substantial non-double-couple component is apparently due to source complexity in which the strike of the fault plane rotated clockwise during rupture, from a strike of approximately 292{degree} to a strike of 302{degree}.

• OSTI ID: 5471339
• Journal Information: United States Geological Survey, Professional Paper; (USA), Vol. 1487
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
CALIFORNIA
EARTHQUAKES
ROCK MECHANICS
ALGORITHMS
CALCULATION METHODS
DATA ANALYSIS
DEPTH
GEOLOGIC FAULTS
GEOLOGIC STRUCTURES
GROUND MOTION
ROTATION
RUPTURES
SEISMIC ARRAYS
SEISMIC P WAVES
SEISMIC WAVES
TIME DEPENDENCE
WAVE PROPAGATION
DEVELOPED COUNTRIES
DIMENSIONS
FAILURES
FEDERAL REGION IX
GEOLOGIC FRACTURES
MATHEMATICAL LOGIC
MEASURING INSTRUMENTS
MECHANICS
MOTION
NORTH AMERICA
SEISMIC EVENTS
USA
580000* - Geosciences