The 2019 Ridgecrest earthquake sequence: Stress triggered by historical earthquakes and imparted stress on surrounding fault systems

Abstract We used various fault models to calculate the stress change on Ridgecrest epicentral locations and surrounding fault systems. In general, the 2019 Ridgecrest earthquake sequence was triggered by past historical earthquakes. The computed stress changes in both foreshock and mainshock epicentral locations have exceeded the stress trigger threshold, which suggests that past historical earthquakes play a key role in driving the Ridgecrest earthquake source structures closer to failure. We calculated the stress on surrounding faults imparted by the Ridgecrest mainshock and its combination with past earthquakes. The Garlock fault is generally stressed by the mainshock, with a maximum of 1.573 bar on central segment. However, our combined model yielded decreased stress on central Garlock fault. Furthermore, we calculated the expected seismicity rate on the Garlock fault and found that the central segment had a higher seismicity rate than the western and eastern segments.