National Archive of Marine Seismic Surveys - About

NAMSS Background

Marine seismic reflection data acquired within the U.S. Exclusive Economic Zone (EEZ) represent an invaluable national scientific resource. Recognizing their importance, the U.S. Geological Survey (USGS) is committed to preserving these data on behalf of the academic community and the nation, ensuring free and unrestricted access to them.

High-quality seismic reflection data are essential for geological investigations offshore. However, much of these data have been proprietary and available for publishable research only under significant restrictions. These data are highly relevant for current and future scientific research and offshore resource evaluation. The value and risk of losing these data were highlighted in a 2002 National Research Council report titled “Geoscience Data and Collections: National Resources in Peril,” produced by the Committee on the Preservation of Geoscience Data and Collections, Committee on Earth Resources.

The National Archive of Marine Seismic Surveys (NAMSS) was initially established to manage data collected by the USGS under the Outer Continental Shelf (OCS) and EEZ mapping programs between 1975 and the mid-1990s. In 2005, major data owners WesternGeco and Chevron transferred over 300,000 km of data from the U.S. eastern, western, and Alaskan coasts to the USGS, aiming to make this information publicly available for research and educational purposes. Additional contributors to NAMSS include British Petroleum, which provided data from the North Slope of Alaska, and Pacific Gas and Electric, which supplied data collected offshore of Diablo Canyon, California, in support of the re-licensing of the Diablo Canyon Power Plant.

Since 2011, the USGS has partnered with the Bureau of Ocean Energy Management (BOEM) to distribute data acquired by BOEM since 1975 for assessing offshore resources. BOEM holds the regulatory authority to acquire and release Geological and Geophysical (G&G) data and information on the Outer Continental Shelf. According to the Code of Federal Regulations (30 CFR Parts 551 and 580), G&G data can be released after the proprietary term of 25 years from the issuance of the G&G permit. Data downloaded from NAMSS are in the public domain and have no restrictions on usage or publication.

NAMSS is managed under the Coastal and Marine Geohazards of the U.S. West Coast and Alaska project at the USGS Pacific Coastal and Marine Science Center in Santa Cruz, California. For additional information and citations, please see the references below.

Kluesner, J., Hart, P., Snyder, G., and Triezenberg, P., 2024, National Archive of Marine Seismic Surveys web portal provides public access to US exclusive Economic Zone Marine Seismic Surveys. Perspectives of Earth and Space Scientists, 5, e2023CN000229. https://doi.org/10.1029/2023CN000229

Triezenberg, P.J., Hart, P.E., and Childs, J.R., 2016, National Archive of Marine Seismic Surveys (NAMSS): A USGS data website of marine seismic reflection data within the U.S. Exclusive Economic Zone (EEZ): U.S. Geological Survey Data Release, doi: 10.5066/F7930R7P.

Most data are provided in SEG-Y format, (Barry, K. M., Cavers, D. A. and Kneale, C. W., 1975, Report on recommended standards for digital tape formats: GEOPHYSICS, 40, no. 02, 344-352, a copy of which can be found at: http://seg.org/News-Resources/Research-and-Data/Technical-Standards.) Specialized software is required to view SEG-Y data. A list of free software that can be used to visualize, analyze, and interpret 2D and 3D SEG-Y data can be found here. Data in the archive have associated metadata: at a minimum shotpoint location information in flat text files. Most surveys also have more complete metadata in the form of text reports and digital images (TIFF) of analog side-labels showing acquisition and in some cases processing parameters. Some profiles are represented by TIFF images of the reflection profile (not digital SEG-Y data). The site attempts to incorporate all metadata that were provided by the contributor. The metadata can be generated in an ISO-compatible XML template consistent with the following metadata standard: Seismic Metadata verson 1.0.

While shotpoint location information is largely complete for all surveys, there may be gaps or erroneous locations and mismatches with the seismic traces. Not all datasets have been quality-controlled to ensure complete correlation between shotpoint locations and seismic profiles.

Marine Geoscience Data System - Lamont-Doherty Earth Observatory

National Centers for Environmental Information - Marine Geology and Geophysics