Source characteristics of large earthquakes at short periods
Short-period (1 to 2 sec) body waves recorded at teleseismic distances from great earthquakes provide information about source rupture processes and strong motions. The maximum P-wave amplitude, the time to the maximum amplitude, and the duration of WWSSN seismograms of great earthquakes were measured. As the seismic moment increases, the above parameter increase. These data support that seismic wave with periods of 1 to 2 sec are generated preferentially in the same regions of the fault plane as waves with periods of 10 to 50 sec. These data can constrain the summation of strong-motion records from a smaller earthquake to predict strong motions from great earthquakes. Spectra of P waves are computed from broadband digital data from GDSN. They are corrected for instrument response, attenuation, geometrical spreading, and radiation pattern to yield a source spectrum from 1 to 30 sec. Source spectra of large, shallow-subduction earthquakes with the same moment have significant differences, presumably due to variations in tectonic setting and strength of seismic coupling. A station-by-station least-squares inversion of broadband GDSN records yields source time functions. A simultaneous, iterative inversion of teleseismic broadband GDSN records yields maps of the spatial distribution of moment release on the fault plane and source time functions.
- Research Organization:
- California Inst. of Tech., Pasadena (USA)
- OSTI ID:
- 5334203
- Country of Publication:
- United States
- Language:
- English
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