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Combined Geophysical Surveys to Investigate the Cause of the Rainfall Induced Shallow Landslide
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 23rd European Meeting of Environmental and Engineering Geophysics, Sep 2017, Volume 2017, p.1 - 5
Abstract
We have conducted the seismic and resistivity surveys at the slope where the shallow landslide induced by heavy rainfall occurred in September, 2015. Resistivity profiles clearly discriminates the unsaturated top soil as higher resistivity zones. We infer the groundwater pathway beneath the top soil from the low resistivity zones. S-wave velocity is good matched with the thickness of the top soil measured by the cone penetration test. At the survey line along the slope parallel to the landslide, the low S-wave velocity and high resistivity has detected within the projected interval of the adjacent landslide. Similar geophysical properties are observed at the survey line above the landslide, which is perpendicular to the slope. These characteristics geophysical properties indicate the weak point that initiates the shallow landslide in the slope.
The combination of the two geophysical surveys helps us to infer the mechanism of the rainfall induced shallow landslides and it is also useful to identify the vulnerable points for the initiation of the shallow landslide in the future.