Peter Dartnell Jane A. Rudebusch James E. Conrad Janet T. Watt Jenna C. Hill 20260402 2.0 data release DOI:10.5066/P9C5DBMR Pacific Coastal and Marine Science Center, Santa Cruz, California U.S. Geological Survey https://doi.org/10.5066/P9C5DBMR Peter Dartnell Jane A. Rudebusch James E. Conrad Janet T. Watt Jenna C. Hill 2021 2.0 data release DOI:10.5066/P9C5DBMR Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey https://doi.org/10.5066/P9C5DBMR Data from various sources, including 2018-2022 multibeam bathymetry data collected by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS), were combined to create a composite 30-m resolution multibeam bathymetry surface of southern Cascadia Margin offshore Oregon and northern California. The data are available as a GeoTIFF file. In 2018 and 2019 the NOAA ships Rainier and Fairweather collected multibeam bathymetry data in five areas along the southern Cascadia Margin offshore northern California and southern Oregon as part of a cooperative project between the U.S. Geological Survey, Pacific Coastal and Marine Science Center and NOAA. Additional data collected by the project between 2021-2022 was subsequently added to the surface in the version 2.0 release along with other publicly available multibeam bathymetry data. The surface was generated to assist research projects studying offshore geohazards including mapping faults, submarine landslides, sediment transport pathways, and seafloor seeps. These data are not intended to be used for navigation. Additional information about the USGS field activities from which some of these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=2018-642-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2019-636-FA https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-643-FA Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology. 1994 2023 ground condition at time data were collected. Complete As needed -125.570471 -124.072995 43.415421 40.159820 USGS Metadata Identifier USGS:b1a31381-7b52-4e71-b488-c9c67c4c030d Global Change Master Directory (GCMD) Bathymetry Seafloor Topography ISO 19115 Topic Category geoscientificInformation USGS Thesaurus bathymetry bathymetry measurement sea-floor characteristics geospatial datasets marine geophysics multibeam sonar Data Categories for Marine Planning Bathymetry and Elevation Marine Realms Information Bank (MRIB) keywords seabed field observation none U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Pacific Coastal and Marine Science Center PCMSC Geographic Names Information System (GNIS) State of Oregon State of California No access constraints USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originators of the dataset and in products derived from these data. Portions of the map used data provided by the Ocean Exploration Trust's (OET) Nautilus Exploration Program, Cruises NA072, NA078, NA080, NA082, NA122, and NA130. This composite bathymetry grid is intended for research purposes only, studying the seafloor morphology of the southern Cascadia margin. The bathymetry grid is not intended to be used for navigation. U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov SouthernCascadia_30m_bathy_image.png Quick view image of the southern Cascadia Margin composite multibeam bathymetry surface PNG Caris HIPS and SIPS (ver. 11), Esri ArcMap (ver. 10.3.1) on a Windows 10 computer, and Esri ArcGIS Pro (ver. 3.5.5) on a Windows 11 computer. The attribute table in the bathymetry source shapefile (SouthernCascadia_bathy_sources_v2.shp) also included in this data release provides mean differences and standard deviations calculated between each dataset and an adjacent, overlapping dataset. In general there is good agreement in depth values between adjacent datasets. No formal logical accuracy tests were conducted. Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. The composite multibeam bathymetry surface was generated from a combination of dedicated multibeam surveys, processed bathymetry surfaces received from other institutions, as well as transit data (ancillary data collected while a ship was underway). The bathymetry data were collected over a span of nearly 30 years using a variety of models of multibeam echosounders, GPS systems, position and motion compensation systems, sound velocity profilers, and tide measurements. The attribute table in the bathymetry source shapefile (SouthernCascadia_bathy_sources_v2.shp), also included in this data release provides links to the survey page for each dataset. Some of the datasets provide metadata and reports that describe mapping procedures and data quality including uncertainty measurements and comparisons with other bathymetry data. The horizontal accuracy of bathymetry data in this data release may be lower than stated in the reports due to further processing of the data. The composite multibeam bathymetry surface was generated from a combination of dedicated multibeam surveys, processed bathymetry surfaces received from other institutions, as well as transit data (ancillary data collected while a ship was underway). The bathymetry data were collected over a span of nearly 30 years using a variety of models of multibeam echosounders, GPS systems, position and motion compensation systems, sound velocity profilers, and tide measurements. The attribute table in the bathymetry source shapefile (SouthernCascadia_bathy_sources_v2.shp), also included in this data release provides links to the survey page for each dataset. Some of the datasets provide metadata and reports that describe mapping procedures and data quality including uncertainty measurements and comparisons with other bathymetry data. The vertical accuracy of bathymetry data in this data release may be lower than stated in the reports due to further processing of the data. The Ocean Exploration Trust's Nautilus Exploration Program collected multibeam echosounder data along the southern Cascadia Margin between 2016 and 2020 (OET survey ID's NA072, NA078, NA080, NA082, and NA122). The U.S. Geological Survey Pacific Coastal and Marine Science Center requested and received both raw line files and processed grids (these data are now available from NOAA, National Centers for Environmental Information, https://ngdc.noaa.gov/mgg/bathymetry/multibeam.html). Raw survey line files were imported and processed in Caris HIPS and SIPS software (version 11). The data were gridded into 30-m surfaces and exported as GeoTIFF's or ASCIIRaster files and imported into ArcMap. 2020 Publicly available multibeam echosounder data available from NOAA, National Centers for Environmental Information were downloaded from https://ngdc.noaa.gov/mgg/bathymetry/multibeam.html. Survey ID's include AT26-02, SKQ201607S, SKQ201804S, HLY18TB, MV1405, TN265, TN240, EX0907, RR1803, and SR1810. The raw survey and transit line files were imported and processed in Caris HIPS and SIPS software (version 11). The data were gridded into 30-m surfaces and exported as GeoTIFF or ASCIIRaster files and imported into ArcMap. 2020 California Seafloor Mapping Program multibeam echosounder data collected nearshore in the State waters of California and southern Oregon (Survey ID's H12130, H12131, H11985, H11983, H11982, H11981, H11980, H1197,9 H11978, H11977, H11976, H11975, H11974, H11973) were downloaded as BAG files from NOAA, NCEI, https://ngdc.noaa.gov/mgg/bathymetry/relief.html. The BAG files were imported into ArcMap and resampled to 30-m resolution. 2020 A processed multibeam bathymetry grid from Monterey Bay Aquarium Research Institute (MBARI) was downloaded as an ASCIIRaster file from http://www3.mbari.org/data/mapping/NorCal_Oregon_Margin/eel_river.htm (EelriverA.asc.gz). The bathymetry data were imported into ArcMap and projected from geographic coordinates to UTM, zone 10, WGS84 coordinates. The UTM grid was reprojected to UTM, zone 10, NAD83 coordinates and resampled to 30-m resolution. 2020 Accessed processed multibeam bathymetry data collected by the USGS during field activity 2014-607-FA. Cochrane, G.R., Dartnell, P., Hemery, L.G., and Hatcher, G., 2017, Data release for USGS field activity 2014-607-FA, Oregon OCS seafloor mapping: selected lease blocks relevant to renewable energy (ver. 2.0, July 2017), U.S. Geological Survey data release, https://doi.org/10.5066/F7V40S8V 2020 Accessed from U.S. Geological Survey Pacific Coastal and Marine Science Center archives, processed multibeam bathymetry data collected in 1994 by the R/V Pacific Hunter as part of the STRATAFORM Project. Mayer, L., and J. Hughes Clarke, (1995). STRATAFORM Cruise Report: R/V Pacific Hunter, Multibeam Survey, July14-28. 2020 In 2018 and 2019 the NOAA ships Rainier and Fairweather mapped five regions along the southern Cascadia Margin (NOAA survey IDs H13117, H13118, H13206, W00474, and W00475) using Kongsberg EM-710 multibeam echosounders. These bathymetry surfaces are available from NOAA, National Centers for Environmental Information and were downloaded from https://ngdc.noaa.gov/mgg/bathymetry/multibeam.html as BAG files. The BAG files were imported into Caris HIPS and SIPS, version 11 and converted to LAS files. The files were imported into ArcMap, version 10.8.1 and converted to grids. 2021 If needed, the previously described bathymetry grids were projected to a common horizontal datum (NAD83) using the "Project Raster" tool in ArcToolbox. Also, if needed, the grids were downsampled to 30-m spatial resolution using the "Resample" tool in ArcMap using the bilinear resampling technique. The grids were then merged together using the "Mosaic to New Raster" tool in ArcMap using the "first" mosaic operator. Priority was given to recent dedicated surveys, then older dedicated surveys followed by cleaner transit data and then noisier transit data. The merged grid was exported as a GeoTIFF file. 2021 In 2021 and 2022 the NOAA ship Fairweather mapped two regions along the southern Cascadia Margin (NOAA survey IDs H13549, H13691) using Kongsberg EM-710 multibeam echosounders. Bathymetry surfaces are available from NOAA, National Centers for Environmental Information at https://ngdc.noaa.gov/mgg/bathymetry/multibeam.html as BAG files. The raw survey and transit line files were obtained from NOAA and imported and processed in Caris HIPS and SIPS software (version 11). The data were gridded into 30-m surfaces and exported as GeoTIFF rasters and then imported into Esri ArcGIS Pro (version 3.5.5). 2023 In 2022 and 2023 the NOAA ship Okeanos Explorer mapped three regions along the southern Cascadia Margin (NOAA survey IDs EX2208, EX2301, EX2307) using Kongsberg EM-304 multibeam echosounders. Bathymetry surfaces are available from NOAA, National Centers for Environmental Information at https://ngdc.noaa.gov/mgg/bathymetry/multibeam.html as GeoTIFF files. The raw survey and transit line files were downloaded, then imported and processed in Caris HIPS and SIPS software (version 11). The data were processed gridded into 30-m surfaces and exported as GeoTIFF rasters and then imported into Esri ArcGIS Pro (version 3.5.5). 2026 In 2021 the Ocean Exploration Trust's E/V Nautilus mapped a region along the southern Cascadia Margin (NA130) using a Kongsberg EM-302 multibeam echosounder. Bathymetry data are available from NOAA, National Centers for Environmental Information at https://ngdc.noaa.gov/mgg/bathymetry/multibeam.html as GSF files. The raw survey and transit line files were downloaded, then imported and processed in Caris HIPS and SIPS software (version 11). The data were processed gridded into 30-m surfaces and exported as GeoTIFF raster and then imported into Esri ArcGIS Pro (version 3.5.5). 2026 Publicly available multibeam echosounder data available from NOAA, National Centers for Environmental Information were downloaded from https://ngdc.noaa.gov/mgg/bathymetry/multibeam.html. Survey ID's include AT42-16 and MGL2211. The raw survey and transit line files were imported and processed in Caris HIPS and SIPS software (version 11). The data were gridded into 30-m surfaces and exported as GeoTIFF files and imported into Esri ArcGIS Pro (version 3.5.5). 2026 The EX2208, EX2301, EX2307, H13549, H13691, NA130, AT42-16, and MGL2211 bathymetry grids were, if needed, projected to a common horizontal datum (NAD83) using the "Project Raster" tool in ArcToolbox. The grids were then merged together with the southern Cascadia composite 30-m resolution surface (version 1.0) using the "Mosaic to New Raster" tool in ArcGIS Pro using the "first" mosaic operator. Priority was given to these datasets as in all cases they were either newer, covered areas that did not exist in the version 1.0 dataset, and/or improved the quality of the data by being less noisy or reducing data artifacts. The merged grid was exported as a GeoTIFF file. 2026 Raster Grid Cell 47618 85490 1 Universal Transverse Mercator 10 0.9996 -123.00000 0.00000 500000.0 0.00 coordinate pair 30.0 30.0 Meters NAD83 GRS80 6378137.00 298.257222101 instantaneous sea level 0.1 meters Explicit elevation coordinate included with horizontal coordinates value Raster values represent depth in meters. Producer defined The complete 30-m resolution "Cascadia_30m_bathy_UTM10_NAD83_v2.tif" grid was originally archived as a TIFF image with the following attributes. >Cell size = 30.0 >Number of rows = 47618 >Number of columns = 85490 > >Data type = floating point > >Boundary >Xmin = -345378 >Xmax = 2219321 >Ymin = 3899099 >Ymax = 5327639 > >Statistics >Minimum value = -3282.3 >Maximum value = -1.0 >Mean = -1488.5 >Standard deviation = 1060.3 > >Coordinate system description >Projection UTM >Zone 10 >Datum NAD83 >Units meter U.S. Geological Survey U.S. Geological Survey - CMGDS Mailing and Physical

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Santa Cruz CA 95060 1-831-427-4747 pcmsc_data@usgs.gov These data are available in GeoTIFF format, including a tif world file (.tfw) and CSDGM FGDC-compliant metadata. Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. GeoTIFF ArcGIS Pro (version 3.5.5) Downloadable zip file contains the TIFF (.tif), and the projection file (.tfw). WinZip 100.6 https://doi.org/10.5066/P9C5DBMR Data can be downloaded using the Network_Resource_Name link and scrolling down to the Sonar Data section. None. The downloadable data file has been compressed with the "zip" command and can be unzipped with Winzip (or other tool) on Windows systems. To utilize these data, the user must have software capable of uncompressing the WinZip file and importing and viewing a GeoTIFF file. 20260402 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998