Monitoring Seismic Temporal Variations by Ambient Seismic Noise Interferometry Technique in a Deep-Seated Landslide Area

Abstract

Summary This study aims to test the feasibility of the correlation calculations from the vertical component of the ambient seismic noise data for monitoring the properties of a deep-seated landslide body. Rigidity in a landslide body is related to seismic velocity. By comparing daily cross-correlation functions (CCF) and autocorrelation functions (ACF) to their reference functions, the rigidity can be monitored. The ambient noise data in the Lantai landslide area, northeast Taiwan were recorded by nine seismometers from August 2016 to December 2018. We utilize the Msnoise package ( Lecocq et al., 2014 ) to derive relative seismic velocity changes (dv/v). Compared to surface displacement data, the results show that the dv/v solutions from ACF can be used for monitoring rigidity changes in a deep-seated landslide. For the Lantai landslide, it is shown that the dv/v variations are corresponding with large amounts of rainfall and an earthquake event (Mw 6.26) in 0.8 – 1.6 Hz and 2 – 6 Hz frequency ranges. While, the dv/v solutions from CCF do not display the relation to any other information. This suggests that to calculate the appropriate solutions of CCF for studying a landslide problem will require more robust testing to evaluate optimal processing parameters.