Landslide monitoring in southwestern China via time-lapse electrical resistivity tomography

The dynamic monitoring of landslides in engineering geology has focused on the correlation among landslide stability, rainwater infiltration, and subsurface hydrogeology. However, the understanding of this complicated correlation is still poor and inadequate. Thus, in this study, we investigated a typical landslide in southwestern China via time-lapse electrical resistivity tomography (TLERT) in November 2013 and August 2014. We studied landslide mechanisms based on the spatiotemporal characteristics of surface water infiltration and flow within the landslide body. Combined with borehole data, inverted resistivity models accurately defined the interface between Quaternary sediments and bedrock. Preferential flow pathways attributed to fracture zones and fissures were also delineated. In addition, we found that surface water permeates through these pathways into the slipping mass and drains away as fissure water in the fractured bedrock, probably causing the weakly weathered layer to gradually soften and erode, eventually leading to a landslide. Clearly, TLERT dynamic monitoring can provide precursory information of critical sliding and can be used in landslide stability analysis and prediction.