Samuel Y Johnson
Seafloor Mapping - Geologic framework, hazards, and habitats
Sam Johnson is a Research Geologist in the U.S. Geological Survey Pacific Coastal and Marine Science Center (PCMSC), an organization of about 100 research and support staff based in Santa Cruz and Menlo Park, CA. He served as PCMSC Center Director from 2003 to 2008. He currently designs, coordinates, and conducts research projects that focus on seafloor and benthic habitat mapping, coastal and marine geomorphology and geologic framework, coastal evolution, and coastal earthquake and tsunami hazards. He helped plan and is the USGS lead for the multi-agency California Seafloor Mapping Program. His present research is focused on active tectonics and hazards offshore central California (Santa Barbara Channel to Cape Mendocino).
Professional Experience
1982-1984 - Assistant Professor, Washington State University
1984 to 2003 - Research Geologist, USGS Energy and Earthquake Hazards Programs
2003 to 2008 - Center Director, USGS Pacific Coastal and Marine Science Center
2008 to 2019 - Research Geologist, USGS Pacific Coastal and Marine Science Center
2019 to present - Research Geologist Emeritus, USGS Pacific Coastal and Marine Science Center
Education and Certifications
B.A. (1975) University of California, Santa Cruz (Earth Sciences)
M.S. (1978) University of Washington (Geological Sciences)
Ph.D. (1982) University of Washington Geological Sciences
Affiliations and Memberships*
Geological Society of America (Fellow)
American Geophysical Union
Society for Sedimentary Geology
Seismological Society of America
Honors and Awards
Department of Interior Distinguished Service Award (2019)
Science and Products
California Seafloor Mapping Program
Coastal and Marine Geohazards of the U.S. West Coast and Alaska
California Seafloor Mapping Program data collection
California Seafloor Mapping Program map-set production
California Seafloor Mapping Program applications
Reprocessed single channel sparker seismic reflection data offshore central California from USGS field activities S-6-08-SC and S-6-09-SC
Geophysical and core sample data collected offshore central California, during field activity 2019-651-FA (ver 2.0, August 2023)
Chirp sub-bottom data of USGS field activity K0211PS collected in Puget Sound, Washington in April of 2011
Quaternary faults offshore of California
Chirp and minisparker seismic-reflection data of field activity F-02-07-NC collected offshore Ano Nuevo to San Francisco, San Mateo County California from 2007-03-22 to 2007-04-06
California State Waters Map Series Data Catalog--Punta Gorda to Point Arena
California State Waters Map Series Data Catalog--Point Sur to Point Arguello
Multichannel minisparker seismic-reflection data of field activity 2015-617-FA; Monterey Bay, offshore central California from 2015-02-23 to 2015-03-06
Marine magnetic data from Point Sur to Piedras Blancas, central California, 2011
Minisparker seismic-reflection data collected between Point Sur and Morro Bay, offshore of central California, from 2011-09-12 to 2011-09-26 (USGS field activity B-05-11-CC)
Marine geophysical data - Point Sal to Refugio State Beach, southern California
Marine Geophysical Data -- Point Arena to Cape Mendocino
Geologic and geophysical maps of the Santa Maria and part of the Point Conception 30'×60' quadrangles, California
Offshore geology and geomorphology from Point Piedras Blancas to Pismo Beach, San Luis Obispo County, California
Marine geology and geomorphology were mapped along the continental shelf and upper slope between Point Piedras Blancas and Pismo Beach, California. The map area is divided into the following three (smaller) map areas, listed from north to south: San Simeon, Morro Bay, and Point San Luis. Each smaller map area consists of a geologic map and the corresponding geophysical data that support the geolog
California State Waters Map Series: Offshore of Refugio Beach, California
California State Waters Map Series — Offshore of San Gregorio, California
California State Waters Map Series: Offshore of Coal Oil Point, California
California State Waters Map Series: offshore of Santa Barbara, California
In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and
California State Waters Map Series: Offshore of Carpinteria, California
California State Waters Map Series — Offshore of Ventura, California
California State Waters Map Series: Offshore of Santa Barbara, California
California State Waters Map Series — Hueneme Canyon and vicinity, California
High-resolution geophysical and geochronological analysis of a relict shoreface deposit offshore central California: Implications for slip rate along the Hosgri fault
Subaqueous clinoforms created by sandy wave-supported gravity flows: Lessons from the central California shelf
Deepwater debrites and linked megaturbidites in confined basins: An example from the Onnuri Basin, East Sea of Korea
Structural controls on slope failure within the western Santa Barbara Channel based on 2D and 3D seismic imaging
Controls on sediment distribution in the coastal zone of the central California transform continental margin, USA
Offshore shallow structure and sediment distribution, Punta Gorda to Point Arena, Northern California
This publication consists of two map sheets that display shallow geologic structure, along with sediment distribution and thickness, for an approximately 150-km-long offshore section of the northern California coast between Punta Gorda and Point Arena. Each map sheet includes three maps at scales of either 1:100,000 or 1:200,000, and together the sheets include 30 figures that contain representati
Offshore shallow structure and sediment distribution, Point Sur to Point Arguello, central California
Shallow structure and geomorphology along the offshore northern San Andreas Fault, Tomales Point to Fort Ross, California
We mapped a poorly documented 35-km-long section of the northern San Andreas fault zone (NSAF) between Tomales Point and Fort Ross, California. Mapping is largely based on high-resolution seismic-reflection profiles (38 fault crossings), multibeam bathymetry, and onshore geology. NSAF strike in this section is nearly parallel to plate motion, characterized by a slight (~2°) northerly (transtension
Controls on submarine canyon head evolution: Monterey Canyon, offshore central California
Neotectonics of the Big Sur Bend, San Gregorio‐Hosgri fault system, central California
California State Waters Map Series — Offshore of Point Conception, California
California State Waters Map Series — Offshore of Gaviota, California
Science and Products
California Seafloor Mapping Program
Coastal and Marine Geohazards of the U.S. West Coast and Alaska
California Seafloor Mapping Program data collection
California Seafloor Mapping Program map-set production
California Seafloor Mapping Program applications
Reprocessed single channel sparker seismic reflection data offshore central California from USGS field activities S-6-08-SC and S-6-09-SC
Geophysical and core sample data collected offshore central California, during field activity 2019-651-FA (ver 2.0, August 2023)
Chirp sub-bottom data of USGS field activity K0211PS collected in Puget Sound, Washington in April of 2011
Quaternary faults offshore of California
Chirp and minisparker seismic-reflection data of field activity F-02-07-NC collected offshore Ano Nuevo to San Francisco, San Mateo County California from 2007-03-22 to 2007-04-06
California State Waters Map Series Data Catalog--Punta Gorda to Point Arena
California State Waters Map Series Data Catalog--Point Sur to Point Arguello
Multichannel minisparker seismic-reflection data of field activity 2015-617-FA; Monterey Bay, offshore central California from 2015-02-23 to 2015-03-06
Marine magnetic data from Point Sur to Piedras Blancas, central California, 2011
Minisparker seismic-reflection data collected between Point Sur and Morro Bay, offshore of central California, from 2011-09-12 to 2011-09-26 (USGS field activity B-05-11-CC)
Marine geophysical data - Point Sal to Refugio State Beach, southern California
Marine Geophysical Data -- Point Arena to Cape Mendocino
Geologic and geophysical maps of the Santa Maria and part of the Point Conception 30'×60' quadrangles, California
Offshore geology and geomorphology from Point Piedras Blancas to Pismo Beach, San Luis Obispo County, California
Marine geology and geomorphology were mapped along the continental shelf and upper slope between Point Piedras Blancas and Pismo Beach, California. The map area is divided into the following three (smaller) map areas, listed from north to south: San Simeon, Morro Bay, and Point San Luis. Each smaller map area consists of a geologic map and the corresponding geophysical data that support the geolog
California State Waters Map Series: Offshore of Refugio Beach, California
California State Waters Map Series — Offshore of San Gregorio, California
California State Waters Map Series: Offshore of Coal Oil Point, California
California State Waters Map Series: offshore of Santa Barbara, California
In 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and
California State Waters Map Series: Offshore of Carpinteria, California
California State Waters Map Series — Offshore of Ventura, California
California State Waters Map Series: Offshore of Santa Barbara, California
California State Waters Map Series — Hueneme Canyon and vicinity, California
High-resolution geophysical and geochronological analysis of a relict shoreface deposit offshore central California: Implications for slip rate along the Hosgri fault
Subaqueous clinoforms created by sandy wave-supported gravity flows: Lessons from the central California shelf
Deepwater debrites and linked megaturbidites in confined basins: An example from the Onnuri Basin, East Sea of Korea
Structural controls on slope failure within the western Santa Barbara Channel based on 2D and 3D seismic imaging
Controls on sediment distribution in the coastal zone of the central California transform continental margin, USA
Offshore shallow structure and sediment distribution, Punta Gorda to Point Arena, Northern California
This publication consists of two map sheets that display shallow geologic structure, along with sediment distribution and thickness, for an approximately 150-km-long offshore section of the northern California coast between Punta Gorda and Point Arena. Each map sheet includes three maps at scales of either 1:100,000 or 1:200,000, and together the sheets include 30 figures that contain representati
Offshore shallow structure and sediment distribution, Point Sur to Point Arguello, central California
Shallow structure and geomorphology along the offshore northern San Andreas Fault, Tomales Point to Fort Ross, California
We mapped a poorly documented 35-km-long section of the northern San Andreas fault zone (NSAF) between Tomales Point and Fort Ross, California. Mapping is largely based on high-resolution seismic-reflection profiles (38 fault crossings), multibeam bathymetry, and onshore geology. NSAF strike in this section is nearly parallel to plate motion, characterized by a slight (~2°) northerly (transtension
Controls on submarine canyon head evolution: Monterey Canyon, offshore central California
Neotectonics of the Big Sur Bend, San Gregorio‐Hosgri fault system, central California
California State Waters Map Series — Offshore of Point Conception, California
California State Waters Map Series — Offshore of Gaviota, California
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government