Tectonic characteristics of the Lishan Piedmont Fault in the SE Weihe Graben (central China), as revealed by the geomorphological and structural analyses

Abstract

The fault kinematics, slip rate and paleoseismicity along the approximate EW-trending Lishan Piedmont Fault (LPF) in the SE Weihe Graben, central China have been determined. The results of geomorphological analysis, field investigations and radiocarbon (14C) age dating indicate that: (i) slope angles of the observed triangular facets cluster around 20°; (ii) empirical correlations yield a vertical slip rate (throw rate) of ~0.11–0.25mm yr−1, which is lower than the neighboring active faults; (iii) the LPF is characterized by almost purely normal slip, and was active within the past ~18,000yr. These findings can provide a basis for the assessment of seismic risk in and around the densely-populated city of Xi'an (an old capital of China). However, we suggest more precise constraints on the fault slip rate and detailed paleoseismological studies on the timing of the most recent earthquake and the repeat time of paleo-earthquakes are needed in order to better understand the seismogenic behaviors of the active LPF.