A Complete Map of Fine-Scale Slip Rate Distribution and Earthquake Potential Along the Haiyuan Fault System

Abstract

We use Sentinel-1 Interferometric Synthetic Aperture Radar observations to derive the first complete map of slip-rate distribution at km-scale along the 1,000-km-long Haiyuan fault system, and further to analyze its earthquake potential. Rate distribution reveals four highly locked asperities (slip rate <1 mm/yr) and three creeping regions (slip rate ranges from 2 to 5 mm/yr) at depths of 0–20 km. Based on the rate distribution, we estimate seismic moment accumulation rate, and by combining historical earthquake records, we calculate the moment deficits on each fault segment. Results show that many fault segments have accumulated a seismic moment that equates to an Mw > 7.0 earthquake. The westernmost fault segment has been rarely mentioned in previous studies, but our calculations show evidently that it is capable of producing Mw > 7.0 earthquakes given the high seismic moment accumulation rate and a lack of small-to-moderate earthquakes.