Seismic response of a slow-moving landslide: exploring data from two years of seismic monitoring at the Hollin Hill Landslide Observatory (UK)

Early-warning of landslide failure relies on understanding subsurface processes that drive slope destabilisation, including changes in moisture content or mechanical behaviour. Material heterogeneity in landslide systems causes spatiotemporal variation in these dynamic processes. There is therefore a need to develop methods that can detect and measure changes in the subsurface to inform landslide stability. Seismic monitoring can record information on the elastic behaviour of the ground in response to immediate and long-term processes, such as slope displacement and moisture variation. Here, we report on data acquired by a seismic network deployed at a slow-moving clay-rich landslide in North Yorkshire UK, representative of many landslides in clay-rich lowland slopes. The temporary network was operational for two years with the aim of understanding how the seismic response of the landslide varies between sensors deployed on parts of the landslide with distinctly different hydrogeological properties. We present an overview of the rationale and deployment procedure, as well as a preliminary assessment of data quality, event analysis, tilt observations, horizontal-to-vertical spectral ratio (H/V) ratio calculations, and ambient noise cross-correlation. We conclude that the moisture dynamics of the slope have a significant influence on observed data, and make further recommendations for the analysis of the dataset. Our study demonstrates the feasibility of analytical techniques using these data, promotes the unique dataset to foster further in-depth analysis, and encourages similar seismological deployments on active landslides.