Abundant Spontaneous and Dynamically Triggered Submarine Landslides in the Gulf of Mexico

Session: Environmental and Near Surface Seismology: From Glaciers and Rivers to Engineered Structures and Beyond [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

Submarine landslides that occur offshore under the ocean are common along the US continental margins, including a very large mapped landslide in the Gulf of Mexico, covering 5509 km² of seafloor. These mass wasting events can trigger tsunamis and hence potentially devastate coastal communities and damage offshore infrastructure, including oil platforms, pipelines and submarine cables. Most commonly, the landslides are identified based on their seafloor scarps from detailed bathymetry. However, the initiation and failure processes of submarine landslides cannot be resolved from bathymetric observations alone and are poorly understood. In addition, the interaction and triggering mechanisms between distant earthquakes and the landslides remains elusive. Here using eight years of continuous records from 2247 seismic stations and a novel detection method, we identify and locate 85 previously unknown submarine landslides in the Gulf of Mexico from 2008 to 2015. Ten of these landslides failed spontaneously while the remaining 75 were dynamically triggered by passing seismic surface waves from distant earthquakes with magnitudes as small as ~5. Our observations demonstrate ongoing submarine landslide activity in the Gulf of Mexico where dense oil platforms are present and that the region is prone to secondary seismic hazard even without local earthquakes. Our results should facilitate future investigations to identify unstable offshore slopes, to illuminate dynamic processes of submarine landslides and to apply remote detection technology in tsunami warning systems. Furthermore, our results offer insight that can help planning efforts to reduce the foreseeable risks posed by such events.

Presenting Author: Wenyuan Fan

Authors