Shallow submarine landslides as a geohazard to coastal infrastructure: examples from NW United Kingdom

Subaqueous mass movement events from seven different coastal locations around NW United Kingdom have been investigated, and their failure types have been assigned. Landslide dimensions and volumes were estimated, and debris lobe runout distances were obtained so as to ascertain the approximate area impacted by each event. In the majority of the case studies, shallow gas within the glaciomarine sediments was noted to be a potential trigger mechanism, along with seismic activity associated with isostatic readjustment of the bedrock following deglaciation.

The evidence suggests that there have been several failure events, along slopes composed of unconsolidated sediment to strong bedrock units, within close proximity to the UK coastline. These events have the potential to impact upon infrastructure in the marine environment, for instance pipelines, cables and aquaculture sitesopen system finfish farms, in addition to coastal infrastructure such as transport routes, piers and jetties, and even waterfront commercial and residential developments.