Time-Lapse Monitoring of Moisture Induced Landslide Using Surface Waves at Hollin Hill Landslide Obsevatory

For about fifteen years, the Hollin Hill site has been used as a landslide research site to test different geophysical characterization and monitoring methods, to assess temporal and spatial stability, and the following methods are regularly evaluated on site: ERT resistivity mapping (Chambers et al. 2010, Uhlemann et al. 2017), self-potential methods SP (Chambers et al. 2008), more recently seismic refraction tomography SRT (Whiteley et al. 2020, Uhlemann et al. 2016). The dynamics and ongoing subsurface processes of the Hollin Hill landslide are therefore relatively well described in literature (Whiteley at al. 2019a). Seismic methods based on characterization of P-wave (Vp) and S-waves (Vs) propagation and in particular on Vp /Vs ratio are commonly used in a landslide context (Grandjean et al. 2009, Mainsant et al. 2012). Since mid-2000, methodological improvements have led to increased routine use of dispersion inversion of Vs in hydrological applications (Pasquet et al. 2015; Dangeard et al. 2016) and in geotechnical applications (Donohue et al. 2011, Bergamo et al. 2016). This abstract therefore discusses current geophysical research to monitor seasonal variations using surface waves content (Rayleigh waves) from SRT acquisitions, in the context of moisture induced landslide monitoring, at the Hollin Hill Landslide Observatory.