Preliminary results on a near-real-time rock slope damage monitoring system based on relative velocity changes following the September 5, 2022 MS 6.8 Luding, China earthquake
Fan Xie, Liang Chen, Shigui Dai, Bo Shao, Huibao Huang, Jinhui Ouyang, Li Li, Éric Larose
Abstract
Relative seismic velocity change (dv/v) is important for monitoring changes in subsurface material properties and evaluating earthquake-induced rock slope damage in a geological disaster-prone region. In this paper, we present a rapid damage assessment on three slow-moving rock slopes by measuring dv/v decrease caused by the 2022 MS 6.8 Luding earthquake in Southwest China. By applying the stretching method to the cross-correlated seismic wavefields between sensors installed on each slope, we obtain earthquake-induced dv/v decreases of ∼2.1%, ∼0.5%, and ∼0.2% on three slopes at distances ranging from ∼86 to ∼370 km to the epicenter, respectively. Moreover, based on seismic data recorded by 16 sensors deployed on the rock slope at a distance of ∼370 km away from the epicenter, a localized dv/v decease region was observed at the crest of the slope by calculating the spatial dv/v images before and after the earthquake. We also derive an empirical in situ stress sensitivity of −7.29✕10−8/Pa by relating the dv/v change to the measured peak dynamic stresses. Our results indicate that a rapid dv/v assessment not only can help facilitate on-site emergency response to earthquake-induced secondary geological disasters but also can provide a better understanding of the subsurface geological risks under diverse seismic loadings.