Slip Rate Dependence of Scaling Relationships for Fault Dimensions and Magnitude
Abstract
In recent work (Anderson et al., 2017, "ABW") we developed new relationships relating magnitude (M) to surface rupture length (L) and fault slip rate (s) for faults in the continental crust. These relations show a systematic effect of slip rate on magnitude estimates of strike-slip faults given a slip rate. We are working on a project to extend slip-rate scaling to rupture displacement and complete the equation set for hazard estimation applications. The previous study found that ruptures of a given length on strike-slip faults with low slip-rates tend to have larger magnitudes similar ruptures on high slip rate faults. One might then expect that the low slip rate faults also would tend to have larger displacements than high slip rate faults of the same rupture length. We have extended the data set used by ABW to include information on the surface slip and downdip rupture width (based on aftershocks or waveform modeling). Our preliminary analysis of the extended data do support the hypothesis that the fault slip is larger on faults with a lower slip rate. Another feature of the ABW results was a proposed closed-form scaling relationship that fits the rupture-length - magnitude data with a constant average stress drop. This relationship fits the available data without increasing the standard deviation. With the extended data set, some modifications to that model may be appropriate. Preliminary results nonetheless are yielding an internally consistent model relating magnitude, rupture length, average displacement, and slip rate that will be suitable for probabilistic seismic hazard models and for constraining fault ruptures for input to models to predict ground motions from finite faults.
Anderson, J. G., G. P. Biasi and S. G. Wesnousky (2017). Bull. Seism. Soc. Am., 107, 2561-2577.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.T13I0352A
- Keywords:
-
- 7209 Earthquake dynamics;
- SEISMOLOGYDE: 7212 Earthquake ground motions and engineering seismology;
- SEISMOLOGYDE: 8110 Continental tectonics: general;
- TECTONOPHYSICSDE: 8118 Dynamics and mechanics of faulting;
- TECTONOPHYSICS