Self-potential variations associated with the slip of Huangnibazi Landslide

The electrical self-potential (SP) responds to the relative fluid flow in porous materials caused by the electrokinetic mechanism, also known as the streaming potential. This characteristic can be used to study landslides induced by rainfall, particularly when subsurface flows cannot be directly observed from the ground surface or landslide scars. The study focuses on the Huangnibazi Landslide, which occurred in 2017 and continued to slide slowly until early 2018 at an average rate of 60 mm/d. SP monitoring was implemented on the slope during the post-failure period to study the characteristics of streaming current. In addition to the diurnal variations of the geoelectric field, localized electric field variations were observed on the morning of Jan. 9, 2018. To examine the spatial distribution and the temporal variation of the streaming current, we processed the measured SP data using a weighted upward continuing method, namely the multi-scale wavelet tomography (MWT). Based on the processing results obtained with the MWT method, we observed variations in the estimated SP sources concentrated in a bulge area. To further investigate these variations, we conducted a numerical modeling test by deforming the geometrical structure of the estimated source. The results suggested that extrusion within the sliding process could be responsible for the variations in SP sources.