The Variation Characteristics of Delay Times of Seismic Signals in Shallow Slopes Under Rainfall Conditions

Seismic velocity is particularly sensitive to clay degradation, measuring relative seismic velocity (dv/v) with seismometers has emerged as a powerful geophysical technique for monitoring ground surface activities. Previous studies have considered the seismic velocity variations over large-scale area under seasonal weather while neglecting the impact of short-term rainfall on clay landslides. We aim to elucidate the quantitative variations of dv/v on shallow clayed slope measured by short-distance sites under rainfall influence. In this study, we deployed five seismometers and one rain gauge on the Juemo Village landslide (Sichuan Province, China) from June 21, 2022, to September 12, 2022. The cross-correlation method was employed to calculate the variations in the travel time of the same seismic phase between two seismic sites. The results show a clear drop in velocity under rainfall conditions, with a relative variation of approximately 15%. The observations could enhance the recognize of slope failure related to rainfall and provide a possible indicator of landslide early warning.