Submarine landslides have various triggers, including large waves produced during hurricanes. Waves produce pressure differences on the seabed, between areas that correspond to the crests and troughs of these waves. This process literally pumps the seabed. On the Mississippi River Delta front, where submarine sediments contain naturally occurring methane gas, this pumping causes gas bubbles in the seabed to contract and expand, liquefying the sediment and triggering a landslide of slushy mud and sediments.

Bentley’s team recently discovered that other activity in the absence of hurricanes, for example waves produced by winter storms and cold fronts and potentially even river floods, can trigger submarine landslides, but these are less well understood.

“With the S.S. Virginia, we found that it doesn’t take major hurricanes to produce slow movement due to landslide processes,” Bentley said. “That was a pretty cool find. It means that the risk of landslides hasn’t changed, as far as we can tell, even though the coastline is receding and the Mississippi River is depositing fewer fresh sediments in the Gulf.”

This summer, Bentley is teaming with scientists at the USGS, the Naval Research Laboratory, and marine geologists at the University of Bremen in Germany to map the seabed in areas of the Gulf that are known to be hotspots for landslides. The team is also taking core samples from mapped areas to better understand the composition of the seafloor in particular areas and how different compositions translate into landslides that are more easily triggered by any wave activity.

Bentley and Kevin Xu, an assistant professor in the LSU Department of Oceanography and Coastal Sciences, are leading the coring program starting this week. A total of 16 faculty members, students and postdocs traveled with Bentley and Xu out of Gulfport, Mississippi on Friday, June 2 to help drive cores into the seabed to learn more about landslide processes.