Specifying initial stress for dynamic heterogeneous earthquake source models
Bulletin of the Seismological Society of America
By: D.J. Andrews and M. Barall
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Abstract
Dynamic rupture calculations using heterogeneous stress drop that is random and self-similar with a power-law spatial spectrum have great promise of producing realistic ground-motion predictions. We present procedures to specify initial stress for random events with a target rupture length and target magnitude. The stress function is modified in the depth dimension to account for the brittle-ductile transition at the base of the seismogenic zone. Self-similar fluctuations in stress drop are tied in this work to the long-wavelength stress variation that determines rupture length. Heterogeneous stress is related to friction levels in order to relate the model to physical concepts. In a variant of the model, there are high-stress asperities with low background stress. This procedure has a number of advantages: (1) rupture stops naturally, not at artificial barriers; (2) the amplitude of short-wavelength fluctuations of stress drop is not arbitrary: the spectrum is fixed to the long-wavelength fluctuation that determines rupture length; and (3) large stress drop can be confined to asperities occupying a small fraction of the total rupture area, producing slip distributions with enhanced peaks.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Specifying initial stress for dynamic heterogeneous earthquake source models |
| Series title | Bulletin of the Seismological Society of America |
| DOI | 10.1785/0120110012 |
| Volume | 101 |
| Issue | 5 |
| Year Published | 2011 |
| Language | English |
| Publisher | Seismological Society of America |
| Contributing office(s) | Earthquake Science Center |
| Description | 10 p. |
| First page | 2408 |
| Last page | 2417 |
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