USGS reveals 6 new California seafloor, coastal maps

April 1, 2016  - By


The U.S. Geological Survey (USGS) released six new sets of publicly available maps that show the diverse and complex range of seafloor habitats along 80 miles of the central California coast from the Monterey Peninsula north to Pigeon Point, according to a news release form the organization.

The new USGS publications, products of the California Seafloor Mapping Program, combine new and legacy data to reveal offshore bathymetry, habitats, geology and seafloor environments in high resolution. Environments range from the rugged granitic bedrock along the coasts of the Monterey Peninsula, to the bedrock reefs that form the surfing point breaks on the Santa Cruz County coast, to the smooth sand and mud in a large delta bar at the mouth of the Salinas River, and to the steep walls and sinuous channels of one of the largest underwater canyon systems in the world.

“The new high-resolution datasets and maps are stimulating research – scientists are excited,” said Sam Johnson, the USGS project lead. “Our stakeholders like to say that you can’t manage it, monitor it or model it if you don’t know what the ‘it’ is. Our seafloor mapping provides that important ‘it’ to the entire coastal community.”

Seamless onshore-offshore geologic maps incorporating subsurface data document the location and geometry of the San Gregorio fault and show how different strands of the fault extend through Carmel Canyon — across the continental shelf west of Santa Cruz and Davenport — and combine to uplift Año Nuevo State Park and Año Nuevo Island. A separate fault system to the east in Monterey Bay is part of an actively deforming wedge of the Earth’s crust caught between the converging San Andreas and San Gregorio faults, the organization said. The six new sets of California maps are Offshore of Pigeon Point, Offshore of Scott Creek, Offshore of Santa Cruz, Offshore of Aptos, Offshore of Monterey Canyon and Vicinity and Offshore of Monterey.

Each publication includes 10 map sheets, a pamphlet and a digital data catalog with web services. The web services are a new addition to the publications and all previous products in the map series, and can be viewed on smartphones. The USGS said the maps and data provide:

  • A foundation for assessing marine protected areas and habitats.
  • An understanding how marine species such as bull kelp, rockfish, crabs and sea otters use the seafloor.
  • Baselines for monitoring coastal change and sea-level-rise impacts.
  • Critical input data for modeling and mitigation of coastal flooding.
  • A framework for understanding coastal erosion and developing regional sediment management plans.
  • Contributions to earthquake and tsunami hazard assessments.
  • More accurate data for safer navigation.
  • Essential information for planning, siting or removing offshore infrastructure.

“These new seafloor maps – used in partnership with the USGS – will give us an additional tool to protect Californians, as well as fish and wildlife,” said John Laird, California’s secretary for natural resources and OPC chair. “The new maps will be used to analyze offshore faults and earthquake hazards. They will also help us identify sources of sand to replenish beaches – and will help establish a scientific baseline to track changes in habitat near shore over time. This investment will pay off for Californians in ways that we cannot even imagine now.”

The California Seafloor and Coastal Mapping Program is supported by the USGS, the California Ocean Protection Council, National Oceanic and Atmospheric Administration, California State University at Monterey Bay, Moss Landing Marine Laboratories and other government, academic and industry partners.

(Click on the images to enlarge them.)

Maps: USGS