Seafloor Fault Expedition 2018

This map shows the faults (red lines) discovered by previous AUV mapping efforts. The light blue circles are proposed dive sites for the upcoming expedition.

MBARI Expedition #447

Expedition goal: During this cruise we will be studying submarine channels and seafloor faults offshore Southern California.

Expedition dates: September 14 – October 2, 2018

Ship: R/V Western Flyer

Research technology:  ROV Doc Ricketts, vibracores, push cores

Expedition chief scientist: Charles Paull

The principal goal of this expedition is to study seafloor faults and submarine channels offshore of Southern California. During this expedition, we will be using the ROV Doc Ricketts to investigate specific features that have been mapped in recently conducted surveys using an autonomous underwater vehicle (AUV).

The extremely detailed AUV maps show evidence of geologically recent fault deformation associated with the San Diego Trough and San Pedro Basin Faults. The maps also provide insight into how the shape of nearby seafloor channels continues to evolve.

The ROV Doc Ricketts will make observations and sample the seafloor at these sites. The AUV data will provide “road maps” that direct the ROV to particular sites and allow the geological samples to be collected in a surgically targeted way. Sediment samples will be collected using vibracores and push cores on the ROV.

Our goal is to establish the timing of movements along these faults and to understand the processes that modify the submarine channels. Weather permitting, we will also deploy a mooring carrying a current meter and a sediment trap to monitor the existing conditions at a potential offshore wind farm site near Morro Bay.

Updates from researchers on the R/V Western Flyer:

Saturday, September 15, 2018
Research Technician Krystle Anderson

Yesterday, we set sail for the Southern California expedition. At the start of every cruise a safety meeting is held for all the participating scientists to learn how the Western Flyer is run and to go over all the ship rules and safety protocols.

During our long transit south, we made a short stop offshore Morro Bay. Crew and scientists woke before dawn to deploy a mooring carrying a sediment trap and current meter at a potential offshore wind farm site. The current meter will measure a profile of bottom currents twice per minute from the seafloor up to 65 meters at the resolution of one-meter intervals. We will be back here in six months to collect the mooring and study the seafloor here in greater detail using the ROV Doc Ricketts.

As we were getting prepared to launch the mooring this morning, we witnessed the final launch of Delta 2 rocket carrying ICESAT-2 satellite off of Vandenberg Air Force Base. The satellite will measure the thickness of the Earth’s polar ice sheets within the accuracy of four millimeters. Watching the launch was an exciting start to the day!

MBARI Cruise Participants