Kolloquium Geoinformatik Near-continuous monitoring of rockfalls and insights into post-seismic landslide patterns

This talk focuses on two strands of research that are both partially underpinned by the importance of using monitoring strategies tailored to the geomorphic change that is under examination. The first section focuses on the improved understanding of rockfall occurrence gained from near-continuous (c. 1 h) LiDAR monitoring of an actively failing coastal rockslope. Current understanding of the nature of rockfall and their controls stems from the capabilities of slope monitoring. These capabilities are fundamentally limited by the frequency and resolution of data that can be captured. An overview of the workflow and, in particular, the practicalities of 4D monitoring is provided. Monitoring at this resolution captures the importance of small rockfalls that ordinarily fail to be discretised due to their superimposition and coalescence, which has important implications for our understanding of the underlying failure mechanisms. Insights into the influence of sub-aerial drivers and the presence of accelerated deformation prior to failure are also presented. The second part of the talk focuses on patterns of landsliding in the years after an earthquake, here the 2015 Gorkha earthquake in Nepal. In addition to triggering ~25,000 coseismic landslides, the earthquake resulted in extensive and pervasive cracking on many hillslopes that did not undergo full coseismic collapse. Monitoring both new and existing landslides is critical for understanding rates of sediment mobilisation, the role of coseismic damage accumulation in driving post-seismic slope failure, and the evolving nature, extent, and severity of landslide risk. Here, initial results are presented from both ground-based monitoring and mapping from medium-resolution satellite imagery. Topographic distributions of new and developing landslides from 2014-2017 are drawn upon to suggest that a return to pre-earthquake landsliding is ongoing.