For the first time, scientists are using advanced technology and an innovative vessel to study, image, and map the unexplored offshore Northern San Andreas Fault from north of San Francisco to its termination at the junction of three tectonic plates off Mendocino, California.

The team includes scientists from NOAA’s National Marine Fisheries Service, Oregon State University, the California Seafloor Mapping Program, the U.S. Geological Survey and Woods Hole Oceanographic Institution. The expedition which concludes Sunday is sponsored by NOAA’s Office of Ocean Exploration and Research.

While the fault on land is obscured by erosion, vegetation and urbanization in many places, scientists expect the subsea portion of the fault to include deep rifts and high walls, along with areas supporting animal life. The expedition team is using high-resolution sonar mapping, subsurface seismic data and imaging with digital cameras for the first-ever three-dimensional bathymetric-structural map that will model the undersea Northern San Andreas Fault and its structure. Little is known about the offshore fault due to perennial bad weather that has limited scientific investigations.Earthquakes in California—especially along the San Andreas Fault—have a critical effect not only locally with property damage and loss of life, but impact the national economy with shipping and transportation interruptions, infrastructure damage and higher insurance premiums for all.

More than a century after the 1906 Great San Francisco Earthquake, the science team is also exploring the fault for lessons associated with the intertwined relationships between major earthquakes and biological diversity. Evidence shows that active fluid and gas venting along fast-moving tectonic systems, such as the San Andreas Fault, create and recreate productive, unique and unexplored ecosystems.  Full release