Coastal landslide monitoring at Aldbrough, East Riding of Yorkshire, UK

P R N Hobbs,D J R Morgan,C V L Pennington,C Dashwood,L D Jones,M P Kirkham

doi:10.1144/qjegh2018-210

Abstract

The paper describes results to date of a continuing monitoring study of coastal ‘soft cliff’ recession at the British Geological Survey9s (BGS9s) Coastal Landslide Observatory (CLO) on the east coast of England at Aldbrough, East Riding of Yorkshire. The cliffed site, part of the 50 km long Holderness coast, consists of glacial deposits, and is one of the most rapidly eroding coastlines in Europe. This rapid rate of erosion provides an ideal opportunity for observation and process understanding because it facilitates the collection of data over periods of time encompassing significant new landslide events at the same location. The results of two approaches are reported: first, terrestrial Light Detection and Ranging (LiDAR) surveying (TLS); second, the installation of instrumented boreholes. The aim of the research is to combine these to investigate the role of landslides and their pre-conditioning factors and the influence of geology, geotechnics, topography and environmental factors on cliff recession. To date, an average recession rate of 1.8 m a−1 and a maximum rate of 3.4 m a−1 have been recorded for the site. The establishment of the CLO and its conceptual geological–geotechnical model are described in a related paper.

Highlights

The paper describes results to date of a continuing monitoring study of coastal ‘soft cliff’ recession at the British
The results show extended periods of pore pressure equilibration for most sensors plus wide variation in the long-term stability of individual sensors, the latter being possibly influenced by temperature variation at the shallowest sensors
The monitoring study at Aldbrough, reported between September and November 2017, has demonstrated that, at a specific site with a 16–17 m high cliff, in glacial deposits typical of the Holderness coast, deep-seated rotational landslides are the dominant agent of cliff recession, possibly with modification towards a composite mode near the toe

Summary

Introduction

The paper describes results to date of a continuing monitoring study of coastal ‘soft cliff’ recession at the British. The cliffed site, part of the 50 km long Holderness coast, consists of glacial deposits, and is one of the most rapidly eroding coastlines in Europe. This rapid rate of erosion provides an ideal opportunity for observation and process understanding because it facilitates the collection of data over periods of time encompassing significant new landslide events at the same location. The value of the application of terrestrial-based Light Detection and Ranging (LiDAR) techniques to monitoring cliff recession is widely recognized (Hobbs et al 2002, 2013; Rosser et al 2005; Poulton et al 2006; Young & Ashford 2006; Quinn et al 2010). Holderness coast has been the subject of intensive study for many decades (Valentin 1971; Pringle 1985; Butcher 1991; Pethick 1996; Prandle et al 1996; Lee & Clark 2002; Newsham et al 2002; Brown 2008; Lee 2008, 2011; Quinn et al 2009, 2010) and recently ‘process-response’ modellers have focused on this coastline

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Conclusion