Seismic Hazards Along the Longmen Shan Fault: Insights from Stress Transfer Between Major Earthquakes and Regional b-Values

Abstract

There are two seismic gaps (Dayi seismic gap and Tianquan-Kangding seismic gap) on the Longmen Shan fault (LMSF), despite the successively occurrence of the 2008 Mw7.9 Wenchuan and 2013 Mw6.6 Lushan earthquakes. To analyze the effects of the Wenchuan and Lushanearthquakes on the LMSF (especially on seismic gaps along the LMSF) and regional seismic hazards, we calculate Coulomb stress changes caused by the Wenchuan and Lushan earthquakes based on a three-dimensional viscoelastic finite element model. We also calculate the spatial distribution of regional b value based on the instrumental seismic catalog before Wenchuan earthquake, and infer the regional background stress level according to the inverse correlation between b value and stress level. The results show that regional earthquakes (including the 2008

A test on methods for Mc estimation and spatial-temporal distribution of b-value in the eastern Tibetan Plateau

“…This is consistent with the study finding that regional seismic activity is mainly concentrated in spatial locations with lower b-value (Nanjo et al, 2012;Zhang and Zhou, 2016;Nanjo and Yoshida, 2018;Jiang and Feng, 2021;Jiang et al, 2022;Sun et al, 2023). Whether an earthquake occurs mainly depends on the background stress that has already accumulated on the fault (Luo and Liu, 2018;Sun et al, 2020;Sun et al, 2023). The characteristic of b-value allows us to use it to understand the characteristics of regional seismic activity distribution (Smith, 1981;Nanjo et al, 2012;Wang et al, 2012;Liu et al, 2015;Gao et al, 2022) and further analyze seismic hazard areas.…”

“…Goebel et al, 2013), this may indicate that there is a high stress accumulation near the epicenters before each of the five earthquakes. This is consistent with the study finding that regional seismic activity is mainly concentrated in spatial locations with lower b-value (Nanjo et al, 2012;Zhang and Zhou, 2016;Nanjo and Yoshida, 2018;Jiang and Feng, 2021;Jiang et al, 2022;Sun et al, 2023). Whether an earthquake occurs mainly depends on the background stress that has already accumulated on the fault (Luo and Liu, 2018;Sun et al, 2020;Sun et al, 2023).…”