Deterministic frequency-wavenumber methods and direct measurements of rupture propagation during earthquakes using a dense array: Data analysis
- Lawrence Livermore National Lab., California (USA)
- Univ. of California, Santa Barbara (USA)
Data recorded by the SMART 1 array in Taiwan are used to make the first direct measurements of two-dimensional earthquake rupture propagation. Using frequency-wavenumber techniques and ray theory, they obtain estimates of the spatial extent, duration, and directions of rupture propagation during two earthquakes located offshore Taiwan. They find that the January 29, 1981, M{sub L} = 6.3 Taiwan earthquake ruptured unilaterally updip and toward the west on a 60{degree} dipping, 109{degrees} striking reverse fault. They suggest that the November 14, 1986, M{sub L} = 7.0 Hualien, Taiwan earthquake was triggered by a shallow (h {approx} 14 km) foreshock M{sub L} = 5.4 which occurred on a subparallel or splay fault approximately 5 s before the mainshock. Comparison of these results with those obtained using teleseismic data suggests either a short duration slip-time function or that most slip occurs near the rupture front. These results indicate that much of the complexity in the seismograms recorded during these events, by the SMART 1 array, is due to spatial and temporal variations of the source. This suggests that, at least in some cases, predictions of both the phase and amplitude of strong ground motion, as a function of time, would require a prior knowledge of source properties. Finally, they recommend siting small ({approx} 10 station) dense arrays on land above offshore subduction zones, which are considered seismic gaps, because they can provide more detailed measurements of rupture propagation than is presently possible.
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5446874
- Journal Information:
- Journal of Geophysical Research; (United States), Vol. 96:B4; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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Deterministic frequency-wavenumber methods and direct measurements of rupture propagation during earthquakes using a dense array: Theory and methods
Related Subjects
EARTHQUAKES
ROCK MECHANICS
DATA ANALYSIS
DIMENSIONS
EARTHQUAKE MAGNITUDE
FREQUENCY DEPENDENCE
GEOLOGIC FAULTS
GROUND MOTION
LENGTH
OFFSHORE SITES
POSITIONING
RUPTURES
SEISMIC ARRAYS
SEISMIC P WAVES
SEISMIC S WAVES
SEISMIC SOURCES
SEISMIC SURVEYS
SEISMOGRAPHS
SLIP
SUBDUCTION ZONES
TAIWAN
TIME DEPENDENCE
WAVE PROPAGATION
ASIA
FAILURES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
ISLANDS
MEASURING INSTRUMENTS
MECHANICS
MOTION
SEISMIC DETECTORS
SEISMIC EVENTS
SEISMIC WAVES
SURVEYS
580000* - Geosciences