Combined Monitoring Methods for Potential Landslides Using MRS and TEM

Abstract

In this research study, the landslide events of Huangshan City in China's Anhui Province were monitored through the integration of two geophysical techniques: the magnetic resonance sounding (MRS) and transient electromagnetic (TEM) methods. The JLMRS-III system was used to determine the distributions of the free water in the strata and the MiniTEM system was utilized to image the subsurface electrical resistivity structures. Data acquisition was carried out on two planned survey lines during a wet season. A set of 15 measurements were completed using MRS array detection; a set of 44 measurements were completed using TEM method. The monitoring activities were repeatedly implemented before and after rainfall occurred. The results of water content information, relaxation time, and resistivity distributions were determined through joint inversion. Plots of the results clearly show the aquifer and resistivity structure of the study area. The monitoring data of displacement, pore-water pressure, and rainfall was collected to help differentiate the slip blocks, slip beds, and slip belts in the accumulation bodies of the landslides. We have delineated the potential landslide area, and determined the sliding depth range at 4 to 8 m. We analyzed the stability of the landslide based on the comparison of water content distribution and the relevant geological information in the sliding body to reveal the possibility of future destruction. The results of this study demonstrated that the combined techniques of MRS and TEM have the capability to effectively monitor potential landslides for key parameters needed for risk assessment.