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Construction of equivalent single planar fault model for strike-slip stepovers

Feng Hu, Jiankuan Xu, Zhenguo Zhang, Wei Zhang, & Xiaofei Chen

Published June 28, 2014, SCEC Contribution #8985

Non-planarity is a common and natural characteristic of seismic faults that strongly affects the rupture dynamics
and the associated seismicwaves. Geometrically uniformplanar faultmodel iswidely used in studies of kinematic
source inversion, seismic hazard estimation and rupture dynamic simulation because of the simplicity and
computational efficiency of this method. The influence of the geometric heterogeneity of faults on rupture
dynamics and associated seismic waves may under some circumstances be reasonably approximated by an
appropriate heterogeneous distribution of shear strength of planar faults, particularly for the case with uniform
initial stress distribution. An outstanding issue is how to approximate the dynamic behavior of a non-planar
fault bymeans of heterogeneous properties on a planar fault. Thus,we propose the construction of an equivalent
planar fault model for a given stepover fault through the introduction of a heterogeneous distribution of static
friction coefficient. Our study shows that the distribution of static friction coefficient on the equivalent planar
fault model is mainly controlled by the geometric irregularities of the stepovers regardless of the initial shear
stress, thereby providing away to quantify the effect of fault geometry, particularly the stepwidth effect in seismic
hazard estimation. Moreover, our results indicate that the influence of geometric discontinuity of stepovers on
rupture dynamics is equivalent to a barrier of the planar fault model.

Hu, F., Xu, J., Zhang, Z., Zhang, W., & Chen, X. (2014). Construction of equivalent single planar fault model for strike-slip stepovers. Tectonophysics, 632(2014), 244-249. doi: 10.1016/j.tecto.2014.06.025.