In March 2020, the U.S. Geological Survey and the University of Puerto Rico Mayagüez (UPRM) Department of Marine Sciences conducted a marine seismic-reflection experiment focused on observing geophysical evidence of submarine faulting and mass wasting related to the southwestern Puerto Rico seismic sequence of 2019–20. The seismic sequence culminated with a magnitude 6.4 earthquake centered beneath Guayanilla Canyon on January 7, 2020 and caused shoreline subsidence, rockfalls, and considerable damage to buildings. The survey was conducted during March 7–13 out of the UPRM Isla Magueyes Laboratories aboard the research vessel Sultana. Approximately 226 line kilometers of multichannel seismic reflection data were collected across the insular shelf and upper slope of the Caribbean Sea between La Parguera and Guayanilla Bay and offshore in the vicinity of Guayanilla Canyon. The seismic profiles image up to 0.5 seconds (approximately 0.5 kilometers) of the sedimentary section beneath the sea floor and provide evidence of faults and mass wasting.

High resolution bathymetric, sea-floor backscatter, and seismic-reflection data were collected offshore of southeastern Louisiana aboard the research vessel Point Sur on May 19-26, 2017, in an effort to characterize mudflow hazards on the Mississippi River Delta front. As the initial field program of a research cooperative between the U.S. Geological Survey, the Bureau of Ocean Energy Management, and other Federal and academic partners, the primary objective of this cruise was to assess the suitability of sea-floor mapping and shallow subsurface imaging tools in the challenging environmental conditions found across delta fronts (for example, variably distributed water column stratification and widespread biogenic gas in the shallow subsurface). Approximately 675 kilometers (km) of multibeam bathymetry and backscatter data, 420 km of towed chirp data, and 550 km of multichannel seismic data were collected. Varied mudflow (gully, lobe), prodelta morphologies, and structural features were imaged in selected survey areas from Pass a Loutre to Southwest Pass.

High resolution bathymetric, sea-floor backscatter, and seismic-reflection data were collected offshore of southeastern Louisiana aboard the research vessel Point Sur on May 19-26, 2017, in an effort to characterize mudflow hazards on the Mississippi River Delta front. As the initial field program of a research cooperative between the U.S. Geological Survey, the Bureau of Ocean Energy Management, and other Federal and academic partners, the primary objective of this cruise was to assess the suitability of sea-floor mapping and shallow subsurface imaging tools in the challenging environmental conditions found across delta fronts (for example, variably distributed water column stratification and widespread biogenic gas in the shallow subsurface). Approximately 675 kilometers (km) of multibeam bathymetry and backscatter data, 420 km of towed chirp data, and 550 km of multichannel seismic data were collected. Varied mudflow (gully, lobe), prodelta morphologies, and structural features were imaged in selected survey areas from Pass a Loutre to Southwest Pass.

Accurate data and maps of sea floor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes due to natural or human impacts. To address these concerns the U.S. Geological Survey, in cooperation with the Massachusetts Office of Coastal Zone Management (CZM), comprehensively mapped the Cape Cod Bay sea floor to characterize the surface and shallow subsurface geologic framework. Geophysical data collected include swath bathymetry, backscatter, and seismic reflection profile data. Ground-truth data, including sediment samples, underwater video, and bottom photographs were also collected. This effort is part of a long-term collaboration between the USGS and the Commonwealth of Massachusetts to map the State’s waters, support research on the Quaternary evolution of coastal Massachusetts, the influence of sea-level change and sediment supply on coastal evolution, and efforts to understand the type, distribution, and quality of subtidal marine habitats. This collaboration produces high-resolution geologic maps and Geographic Information System (GIS) data that serve the needs of research, management and the public. Data collected as part of this mapping cooperative continue to be released in a series of USGS Open-File Reports and Data Releases (https://www.usgs.gov/centers/whcmsc/science/geologic-mapping-massachusetts-seafloor). This data release provides the geophysical and geologic sampling data collected in Cape Cod Bay during USGS Field Activities 2019-002-FA and 2019-034-FA in 2019.

High-resolution multichannel minisparker seismic-reflection data were collected by the U.S. Geological Survey in July of 2018 between Point Conception and Coal Oil Point in the Santa Barbara Channel, California. Data were collected aboard the USGS R/V Parke Snavely during field activity 2018-645-FA, using SIG 2-mille minisparker and recorded using an 8-channel Geometrics digital hydrophone streamer. Sub-bottom acoustic penetration spans several hundreds of meters and is variable by location.

High-resolution multichannel minisparker seismic-reflection data were collected by the U.S. Geological Survey in July of 2018 between Point Conception and Coal Oil Point in the Santa Barbara Channel, California. Data were collected aboard the USGS R/V Parke Snavely during field activity 2018-645-FA, using SIG 2-mille minisparker and recorded using an 8-channel Geometrics digital hydrophone streamer. Sub-bottom acoustic penetration spans several hundreds of meters and is variable by location.

Shapefile showing tracklines of Multichannel Seismics Survey Collected During USGS Cruise M1-98-GM. This cruise was to the Mississippi Canyon region of the Gulf of Mexico, and data were collected along 555 km of tracklines. During June 1998 and April 1999, the U.S. Geological Survey (USGS) conducted two research cruises in the northern Gulf of Mexico to acquire high-resolution seismic reflection data across the upper and middle continental slope as part of an investigation of the seismic character, distribution, and potential effects of naturally-occurring marine gas hydrates and related free gas within the gas hydrate stability zone. Over 1600 km of two-dimensional multichannel seismic reflection profiles were acquired during these two cruises. The specific objectives of this investigation are (a) to produce high-resolution images of the gas hydrate stability zone; (b) to study the distribution and character of potential seafloor failures and their relationship to known and inferred gas hydrate deposits; (c) to look at systematic variations in subsurface structure in gas hydrate and non-hydrate areas; and (d) to estimate, if possible, the amounts of hydrates present within the gas hydrate stability zone. The multichannel profiles provide high-quality images with approximately 5 meters of vertical resolution and up to 2 km of penetration. This report gives an overview of the acquisition and data processing of the multichannel seismic reflection profiles and provides references and links to reports with more detailed information. Geologic interpretations of these seismic profiles regarding gas hydrate occurrence and distribution within the study areas of this investigation are given in Hart and others (2002).

High resolution bathymetric, sea-floor backscatter, and seismic-reflection data were collected offshore of southeastern Louisiana aboard the research vessel Point Sur on May 19-26, 2017, in an effort to characterize mudflow hazards on the Mississippi River Delta front. As the initial field program of a research cooperative between the U.S. Geological Survey, the Bureau of Ocean Energy Management, and other Federal and academic partners, the primary objective of this cruise was to assess the suitability of sea-floor mapping and shallow subsurface imaging tools in the challenging environmental conditions found across delta fronts (for example, variably distributed water column stratification and widespread biogenic gas in the shallow subsurface). Approximately 675 kilometers (km) of multibeam bathymetry and backscatter data, 420 km of towed chirp data, and 550 km of multichannel seismic data were collected. Varied mudflow (gully, lobe), prodelta morphologies, and structural features were imaged in selected survey areas from Pass a Loutre to Southwest Pass.

In summer 2018, the U.S. Geological Survey partnered with the U.S Department of Energy and the Bureau of Ocean Energy Management to conduct the Mid-Atlantic Resources Imaging Experiment (MATRIX) as part of the U.S. Geological Survey Gas Hydrates Project. The field program objectives were to acquire high-resolution 2-dimensional multichannel seismic-reflection and split-beam echosounder data along the U.S Atlantic margin between North Carolina and New Jersey to determine the distribution of methane gas hydrates in below-sea floor sediments and investigate potential connections between gas hydrate dynamics and sea floor methane seepage. MATRIX field work was carried out between August 8 and August 28, 2018 on the research vessel Hugh R. Sharp and resulted in acquisition of more than 2,000 track-line kilometers of multichannel seismic-reflection and colocated split-beam echosounder data, along with wide-angle seismic reflection and refraction data from 63 expendable sonobuoy deployments.

High-resolution multichannel minkisparker seismic-reflection (MCS) profiles were collected by the U.S. Geological Survey in September and October of 2016 from the northern portion of the Santa Barbara Basin offshore southern California. Data were collected aboard the USGS R/V Parke Snavely and NOAA R/V Shearwater during field activity 2016-666-FA using a SIG 2-mille minisparker and recorded using 48- or 24-channel Geometrics digital hydrophone streamer. Sub-bottom acoustic penetration spans several hundreds of meters and is variable by location.