Spatial and Temporal Patterns of Rockfalls in Hard Rock Coastal Cliffs

Whadcoat, S.K.; Rosser, N.J.; Brain, M.J.; Hardy, R.J.

Abstract

Rock cliffs have been observed to evolve via progressive failure, yet the processes that control progressive failure and how it is spatially manifest are poorly understood. This paper considers the spatial and temporal distribution of rockfalls from high resolution field monitoring data of hard rock coastal cliffs, and identifies patterns that characterize rockfall evolution. In doing so, this paper seeks to address the gaps in current understanding of rock cliff evolution via progressive failure. Terrestrial laser scans of coastal cliffs in North Yorkshire (UK) were collected monthly over two years. Results show observations of the rockfalls that are indicative of progressive failure, as the propagation of small rockfalls appears to be the mechanism dominating the rate of material loss from these cliffs. This has been demonstrated via observations of directionality in rockfall propagation and growth across the cliff face; evidence that rockfalls cluster significantly at a range of scales; and temporal patterns in rockfall behavior. The findings demonstrate that variability exists beyond what can be explained by geological and environmental variability. Using high resolution TLS data to show that the observed clustering and sequencing of rockfalls operate over identifiable length scales in space and time, this paper provides an indication of the processes that may be governing these mechanisms of erosion. Finally, analysis of the dataset presented also provides context and information to inform the development of an approach to 3D numerical rock cliff modelling that is capable of simulating rockfall evolution in the manner observed here.

Citation

Whadcoat, S., Rosser, N., Brain, M., & Hardy, R. Spatial and Temporal Patterns of Rockfalls in Hard Rock Coastal Cliffs. In J. De Graff, & A. Shakoor (Eds.), Landslides: Putting Experience, Knowledge and Emerging Technologies into Practice (633 - 644). Association of Environmental & Engineering Geologists (AEG)

• Deposit Date: Jun 27, 2017
• Pages: 633 - 644
• Book Title: Landslides: Putting Experience, Knowledge and Emerging Technologies into Practice