Peter Dartnell Daniel S. Brothers Peter J. Haeussler 20220919 GeoTIFF data release DOI:10.5066/F7JH3KG6 Pacific Coastal and Marine Science Center, Santa Cruz, California U.S. Geological Survey https://doi.org/10.5066/F7JH3KG6 https://www.sciencebase.gov/catalog/item/5abc0e9ce4b081f61abd5c61 Peter Dartnell Daniel S. Brothers Peter J. Haeussler 2022 data release DOI:10.5066/F7JH3KG6 Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey https://doi.org/10.5066/F7JH3KG6 https://www.sciencebase.gov/catalog/item/5abbf417e4b081f61abd5bd2 These metadata describe bathymetry collected during a 2015 multibeam echosounder survey near Cross Sound, southeast Alaska. Data were collected by the U.S. Geological Survey (USGS) and the Alaska Department of Fish and Game (ADFG) aboard the ADFG R/V Solstice during USGS field activity 2015-629-FA. The bathymetry data are published here as a 32-bit GeoTIFF image. These metadata describe the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC) 2015 bathymetry data collected near Cross Sound, southeast Alaska that is provided as a 10-m resolution TIFF image. In 2015 the U.S. Geological Survey (USGS), Pacific Coastal and Marine Science Center (PCMSC)in cooperation with the Alaska Department of Fish and Game (ADFG) collected bathymetry and acoustic backscatter data near Cross Sound in southeast Alaska using an Reson 7111 multibeam echosounder mounded to the ADFG R/V Solstice. The survey was conducted to map the offshore expression of the Queen Charlotte fault system that runs for approximately 500 kilometers off the coast of southeast Alaska and British Columbia. This was the first in a series of surveys to map the entire offshore component of the fault. The fault system has generated numerous powerful earthquakes in the magnitude 7 and 8 range. This new mapping will help understand the fault's slip rate, earthquake recurrence intervals, and paleoseismic history. These data are intended for science researchers, students, policy makers, and the general public. These data can be used with geographic information systems or other software to identify bathymetric features. These data are not intended to be used for navigation. Additional information about the field activities from which these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=2015-629-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. 20150505 20150521 ground condition at time data were collected. Complete As needed -137.202 -136.217 58.426 57.808 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 USGS Metadata Identifier USGS:5abc0e9ce4b081f61abd5c61 Geographic Names Information System (GNIS) State of Alaska Cross Sound Queen Charlotte Fault Icy Point Lisianski Inlet Graves Harbor Yakobi Sea Valley None 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 and the Alaska Department of Fish and Game as the originators of the dataset and in products derived from these data. This information is not intended for navigation purposes. U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

2885 Mission Street

Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov https://www.sciencebase.gov/catalog/file/get/5abbf417e4b081f61abd5bd2?name=CrossSound_2015_bathy_10m_UTM08_WGS84_QV.jpg&allowOpen=true Quick view image of 2015 Cross Sound shaded-relief bathymetry data JPEG Caris HIPS and SIPS (ver. 9) and ArcMap (ver. 10.3.1) on a Windows 7 computer. Not applicable for raster data. No formal logical accuracy tests were conducted. A couple of transit or test lines that are in the tracklines shapefile are not included in the bathymetry grid. 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 Coda Octopus F180 position and motion compensation system has a horizontal positional accuracy of about 0.4 m with DGPS correstions and roll and pitch accuracies of about 0.025 degrees (https://www.oceanscan.net/gallery/Data_Sheets/CODA_F180_PRECISION_ALTITUDE__POSITIONING_SYSTEMS.pdf). Accuracies of final products may be lower due to water depth and total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations. The Coda Octopus F180 position and motion compensation system has heave accuracy between 3.5cm - 5cm (https://www.oceanscan.net/gallery/Data_Sheets/CODA_F180_PRECISION_ALTITUDE__POSITIONING_SYSTEMS.pdf). Accuracies of final products may be lower due to water depth and total propagated uncertainties of the mapping systems, which include sonar system, position and motion compensation system, and navigation, as well as data processing that includes sounding cleaning, gridding, and datum transformations. In May 2015 the USGS, PCMSC mapped offshore Cross Sound in southeast Alaska over the northern section of the Queen Charlotte fault. A Reson 7111 multibeam echosounder was pole-mounted to the Alaska Department of Fish and Game R/V Solstice. The survey line files were imported into Caris HIPS and SIPS software (version 9) for bathymetric processing. Water column sound velocity data that was collected throughout the survey was applied to the bathymetry data and verified tides from the Elfin Cove tide station (9452634) were applied in post-processing. The data were cleaned of obvious bad soundings and the soundings were gridded into a 10-m surface. The surface was exported as an ASCIIRaster file and imported into a Geographic Information System (GIS). The bathymetry grid was transformed to UTM zone 8, WGS84 coordinates, vertically referenced to the WGS84 ellipsoid using datum offset values from NOAA's VDatum tool, https://vdatum.noaa.gov/welcome.html. A value of 0.12m was added to the MLLW grid to transform to NAVD88 and then a value of 3.1m was added to transform to WGS84. The bathymetry grid was then exported as a GeoTIFF file in UTM zone 8, WGS84 coordinates, vertically reference to the WGS84 ellipsoid (CrossSound_2015_bathy_10m_UTM08_WGS84_WGS84.tif). 2020 Raster Grid Cell 6746 5632 1 Universal Transverse Mercator 8 0.9996 -135.00000 0.00000 500000.0 0.00 row and column 10.0 10.0 Meters WGS84 WGS84 6378137.00 298.257223563 World Geodetic Datum 1984 0.1 meters Explicit elevation coordinate included with horizontal coordinates value depth in meters relative to the WGS84 ellipsoid Producer defined The complete 10-m resolution 2015 Cross Sound bathymetry grid was originally archived as a TIFF image with the following attributes. >Cell size = 10.0 >Number of rows = 6746 >Number of columns = 5632 > >Data type = floating point > >Boundary >Xmin = 371385 >Xmax = 427705 >Ymin = 6409385 >Ymax = 6476845 > >Statistics >Minimum value = -427.54 >Maximum value = -6.74 >Mean = -190.72 >Standard deviation = 91.60 > >Coordinate system description >Projection UTM >Zone 8 >Datum WGS84 >Vertical Reference WGS84 >Units meter U.S. Geological Survey U.S. Geological Survey - ScienceBase Mailing and Physical

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 1-888-275-8747 sciencebase@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 ArcMap (version 10.3.1) Downloadable zip file contains the TIFF (.tif) and the projection file (.tfw). WinZip 17 https://www.sciencebase.gov/catalog/file/get/5abc0e9ce4b081f61abd5c61 https://www.sciencebase.gov/catalog/item/5abc0e9ce4b081f61abd5c61 https://doi.org/10.5066/F7JH3KG6 Data can be downloaded using the Network_Resource_Name links. The first link is a direct link to download the zipped file of the bathymetry data. The second link points to a landing page with data, metadata, and a browse image. The third link points to the landing page for the entire data release, including links to pages of the various data files. 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. 20220919 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

2885 Mission Street

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