Upgrading a synthetic seismicity model for more realistic fault ruptures

Abstract

A quasi-static synthetic seismicity model for multiple interacting faults of any orientation is upgraded to include a more realistic rupture model. In the original model entire ruptures, covering many fault patches, occur instantaneously and rupture propagation is ignored. Now time is introduced into the rupture process via a patch interaction delay in proportion to distance/shear wave velocity. Also, to try to mimic observed rise times for real earthquakes, a simple time dependent friction law is used. Comparison of results for the old and new models for a simple case of two strike-slip faults show that clustering of large events is somewhat reduced in the new model. It remains to be seen if this conclusion will be verified in more complex fault networks. The new model takes about twice as much computation time, but the results may now be used to calculate synthetic seismograms.