U.S. Geological Survey 20200409 1.0 digital data data release DOI:10.5066/P9Y1MSTN Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts U.S. Geological Survey, Coastal and Marine Geology Program https://doi.org/10.5066/P9Y1MSTN https://www.sciencebase.gov/catalog/item/5e28b586e4b0d3f93b05fe2b Wayne E. Baldwin Eric M. Moore Charles R. Worley Alex R. Nichols Carolyn D. Ruppel 2020 1.0 data release DOI:10.5066/P9Y1MSTN Reston, VA U.S. Geological Survey Suggested citation: Baldwin, W.E., Moore, E.M., Worley, C.R., Nichols, A.R., and Ruppel, C.D., 2020, Marine Geophysical Data Collected to Support Methane Seep Research Along the U.S. Atlantic Continental Shelf Break and Upper Continental Slope Between the Baltimore and Keller Canyons During U.S. Geological Survey Field Activities 2017-001-FA and 2017-002-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P9Y1MSTN. https://doi.org/10.5066/P9Y1MSTN https://www.sciencebase.gov/catalog/item/5e179176e4b0ecf25c59f97a In spring and summer 2017, the U.S. Geological Survey’s Gas Hydrates Project conducted two cruises aboard the research vessel Hugh R. Sharp to explore the geology, chemistry, ecology, physics, and oceanography of sea-floor methane seeps and water column gas plumes on the northern U.S. Atlantic margin between the Baltimore and Keller Canyons. Split-beam and multibeam echo sounders and a chirp subbottom profiler were deployed during the cruises to map water column backscatter, sea-floor bathymetry and backscatter, and subsurface stratigraphy associated with known and undiscovered sea-floor methane seeps. The first cruise, known as the Interagency Mission for Methane Research on Seafloor Seeps and designated as field activity 2017-001-FA, was conducted from May 4 to May 11, 2017, and acquired geophysical data to support remotely operated vehicle exploration of seep sites using the Global Explorer, which is operated by Oceaneering International, Inc. Geophysical operations during cruise 2017-002-FA from August 25 to September 6, 2017, were also focused on mapping water column methane plumes, sea-floor seep sites, and subseafloor strata, but primarily supported conductivity, temperature, and depth instrument deployment, surface-water methane-concentration mapping, and water-sampling operations as part of a collaborative study with the University of Rochester of the effect of methane seepage on ocean water biogeochemistry. The National Oceanic and Atmospheric Administration’s Office of Ocean Exploration and Research partially sponsored cruise 2017-001-FA, and the U.S. Department of Energy partially sponsored both cruises. This dataset contains point and trackline navigation data for four ROV Global Explorer dives tracked using an Applied Acoustics EasyTrack Nexus 2 ultra-short baseline system during USGS field activity 2017-001-FA along the U.S. Atlantic continental shelf break and upper continental slope between Baltimore and Keller Canyons. This information allows for spatial correlation of the video, photography, bathymetry, and geologic samples collected by the ROV during the dives with other geophysical data for investigating sea-floor ecology, chemistry, morphology, and stratigraphy in the area. Support for 2017-001-FA was provided to the USGS by NOAA and DOE through interagency agreements 16-01118 and DE-FE0023495, respectively. Additional information on the field activity is available from https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-001-FA. Additional information specific to the Interagency Mission for Methane Research on Seafloor Seeps is available at https://www.usgs.gov/centers/whcmsc/science/immerss-interagency-mission-methane-research-seafloor-seeps?qt-science_center_objects=0#qt-science_center_objects and https://archive.usgs.gov/archive/sites/soundwaves.usgs.gov/2017/05/outreach.html. 20170508 20170511 ground condition Complete None planned -74.477562 -73.821625 38.047653 36.869959 USGS Metadata Identifier USGS:5e28b586e4b0d3f93b05fe2b None U.S. Geological Survey USGS Woods Hole Coastal and Marine Science Center WHCMSC Coastal and Marine Hazards and Resources Program CMHRP Department of the Interior DOI National Oceanic and Atmospheric Administration - Office of Ocean Exploration and Research NOAA-OER Department of Energy DOE field activity number 2017-001-FA HRS1704 Interagency Mission for Methane Research on Seafloor Seeps IMMeRSS R/V Hugh R. Sharp shapefile trackline navigation USBL navigation USBL Applied Acoustics EasyTrack Nexus 2 ROV navigation ROV Global Explorer marine geology ISO 19115 Topic Category location geoscientificInformation oceans USGS Thesaurus marine geophysics marine geology navigational data geospatial datasets None United States of America Atlantic Ocean Atlantic Margin Baltimore Canyon Accomac Canyon Washington Canyon Norfolk Canyon Keller Canyon Chincoteague Ridge None sea floor seafloor none 2017 None Public domain data from the U.S. Government are freely distributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset. U.S. Geological Survey Wayne Baldwin Geologist mailing and physical

384 Woods Hole Road

Woods Hole Massachusetts 02543-1598 US 508-548-8700 x2226 508-457-2310 wbaldwin@usgs.gov https://www.sciencebase.gov/catalog/file/get/5e28b586e4b0d3f93b05fe2b/?name=2017-001-FA_ROVUSBLNav_browse.jpg ROV USBL navigation trackline at Chincoteague Ridge. JPG Demopoulos, A. McClain-Counts, J. Bourque, J. Prouty, N. Smith, B. Brooke, S. Ross, S. Ruppel, C. 2019 1.0 document Deep Sea Research Part I 148, pp.53-66 Amsterdam, Netherlands Elsevier https://doi.org/10.1016/j.dsr.2019.04.002 Ruppel, C. Demopoulos, A. Prouty, N. 2018 1.0 document Supplement to Oceanography 31(1), p.93 Rockville, MD The Oceanography Society https://doi.org/10.5670/oceanog.2018.supplement.01 ROV dives tracked using the USBL navigation system were conducted during daytime operations (generally between approximately 10:00 and 23:00 UTC) on May 8-11 (JD128 - JD130), 2017. Navigation for four dives, numbered 3-6 are included in the shapefiles '2017-001-FA_ROVUSBLNavPoints.shp' and '2017-001-FA_ROVUSBLTracklines'. USBL navigation was not available during the first offshore dive of the field activity at Washington Canyon on May 4, 2017 (JD124) due to inoperability of the USBL system. Additionally, USBL navigation collected during the second dive within the Delaware River estuary on May 7, 2017 (JD127) for system troubleshooting is not included in the data release. Ship navigation was supplied to the Applied Acoustics EasyTrack Nexus 2 USBL system from the ships POS/MV inertial navigation system with intermittent success through May 4 (JD124) of 2017-001-FA, but for the remainder of the cruise ship navigation was supplied by a Hemisphere GPS receiver with the GPS antenna mounted on the aft 01 deck handrail approximately 3.4 meters aft and 4 meters to port of the USBL transceiver. The USBL acoustic transceiver was mounted in the rear slot of the retractable keel of the R/V Hugh R. Sharp, which is located approximately amidships on the center line of the vessel, and two 1100 series remote beacons mounted on the ROV main vehicle and controller pod, respectively. The USBL system calculated the bearing and slant range between the transceiver and remote beacons, as well as depths and positions of the beacons relative to the ship, corrected for pitch, roll, and installation offsets. HYPACK calculated the final positions of the ROV vehicle by applying the computed relative offsets to ship positions at corresponding UTC times. GPS horizontal positional accuracy is assumed to be within 3 m and accuracy of the positions and bearings can be up to 0.12 percent of the slant range and 0.01 degrees, respectively. After filtering the calculated positions (see description in the processing steps below) to remove scatter of up to a kilometer outside of the dive area footprints, the accuracy of the remaining positions are estimated to be within 50 meters. Factors possibly contributing to uncertainties in the calculated positions include calibration of the system in an environment considerably different from the survey area (estuary versus offshore), inadequate characterization of water column sound speeds, or acoustic interference from other water column noise sources (multipath interference, bubble wash beneath the ships keel, interference with the concurrently operated split-beam sonar). U.S. Geological Survey unpublished material digital data disc 20170508 20170511 ground condition SEG-Y SB-512i data The Applied Acoustics EasyTrack Nexus 2 USBL system was used to provide navigation for ROV Global Explorer dives during field activity 2017-001-FA. The system consisted of a hemispherical acoustic transceiver mounted in the rear slot of the retractable keel of the R/V Hugh R. Sharp, which is located approximately amidships on the center line of the vessel, and two 1100 series remote beacons mounted on the ROV main vehicle and controller pod, respectively. Ship navigation was initially supplied to the USBL system from the ships POS/MV inertial navigation system with intermittent success through May 4 (JD124) of 2017-001-FA, but for the remainder of the cruise ship navigation was supplied by a Hemisphere Differential GPS (DGPS) receiver with the DGPS antenna mounted on the aft 01 deck handrail approximately 3.4 meters aft and 4 meters to port of the USBL transceiver. While surveying, the retractable keel was lowered to 1-meter below the hull, resulting in a draft of 5.06 meters below the waterline. The EasyTrack Nexus 2 (version 2.0.2.1) software controlled the USBL system acquisition, logged the raw data stream (*.epb format), and output calculated bearing, slant range, depth, and position of the ROV vehicle relative to the ship (corrected for pitch, roll, and installation offsets) as an ORE Trackpoint 2EC string over a serial connection. HYPACK (version 2017, 17.1.3.0) survey software was used to monitor the serial connection using its 'Trackp.dll' driver, calculate the position of the ROV in WGS84, UTM 18 North, meters, and log the string transmitted from USBL system and the calculated position as messages in the HYPACK raw files. A network protocol time server was used to synchronize both the USBL and HYPACK acquisition computers to GPS time. Calibration procedures for the USBL system were conducted in the Delaware River estuary prior to conducting dives 3 - 5. Sound velocity profiles calculated from XBT casts were provided to the EasyTrack Nexus 2 software for use in range calculations. PROCESS STEP 1: Unix shell programs were used to extract a subset of USBL position data and group the data by dive as follows: 1)'grep' was used to extract all USBL ROV position messages from HYPACK raw files; the messages were piped to 'awk', which conditionally filtered the input to create a subset containing every fifth input message, converted the HYPACK time stamp (in seconds after midnight) to a fractional day value (divided by 86400 seconds/day), and printed the HYPACK time stamp, fractional day value, easting, and northing values to temporary output ASCII text files. 2) 'cat' was used to concatenate all temporary text files for each dive into a single file per dive. Process steps 1 and 2 were conducted by Carolyn Ruppel. 201705 U.S. Geological Survey Carolyn D. Ruppel Geophysicist mailing and physical address

384 Woods Hole Rd.

Woods Hole MA 02543-1598 (508) 548-8700 x2339 (508) 457-2310 cruppel@usgs.gov PROCESS STEP 2: Microsoft Excel 2019, ArcMap (version 10.5), and XTools Pro (version 19) were used to edit and create point and trackline shapefiles from the individual dive ASCII text files: 1) The ASCII text files for each dive were opened in Excel and the fractional day column was converted to hh:mm:ss time format in the process. Each file was saved to the comma separated values (CSV) format with headers for each column. 2) Navigation data for each dive were imported from the CSV files into ArcMap (Add XY data) specifying WGS84, UTM 18 North as the coordinate system and saved to new point shapefiles. 3) XTools Pro polylines from points was used to create a trackline shapefile from each new point shapefile using FID as the sort order field. 4) Point and polyline shapefile pairs were examined together to evaluate the data for obviously erroneous navigation points (easily identified by impossibly large polyline deviations). Points identified as outliers were eliminated from the point shapefiles and after saving changes, the polylines from points operation was repeated to create a new dive trackline from the edited point data. In some instances this was an iterative process. 5) The ArcMap data frame was reprojected from UTM 18N to WGS84 geographic coordinate system, then field names for longitude and latitude were added to the attribute tables of the point shapefiles and each were populated using calculate geometry in WGS84 geographic coordinates. Each point and polyline shapefile was exported to new geographic files using the coordinates of the data frame. 201705 PROCESS STEP 3: XTools Pro and ArcMap (10.7.1) were used to modify the attribute tables of the geographic point and polyline shapefiles and merge them into one file each containing data for all the dives. 1) XTools Pro modify table was used to delete (HYPACK time stamp), define and populate by expression (DiveOp, Year, JD_UTC, SurveyID, VehicleID, RovID, and DeviceID), and reorder fields in the individual dive point shapefile attribute tables. The resulting fields are "East, North, Lon, Lat, DiveOp, Year, JD_UTC, SurveyID, VehicleID, RovID, and DeviceID. 2) ArcMap Merge was used to combine the point (with modified tables) and polyline shapefiles from each dive into a single file for each feature type; '2017-001-FA_ROVUSBLNavPoints.shp' and '2017-001-FA_ROVUSBLTracklines.shp', respectively. 3) XTools Pro modify table was used to define the fields "DiveOp, Year, JDUTC_init, JDUTC_end, SurveyID, VehicleID, RovID, and DeviceID" in the attribute table of '2017-001-FA_ROVUSBLTracklines.shp'. The field s "Year, SurveyID, VehicleID, RovID, and DeviceID" were populated by expression using the field calculator, and "DiveOp, JDUTC_init, JDUTC_end" were populated by hand with values copied from the attribute tables of the individual dive point shapefiles. 4) XTools Pro calculate geometry was used to create the field "Length_km" in the attribute table of '2017-001-FA_ROVUSBLTracklines.shp' and populate it with the lengths of each polyline feature in the file calculated in WGS84, UTM 18 North, kilometers. 202001 U.S. Geological Survey Wayne E. Baldwin Geologist mailing and physical address

384 Woods Hole Rd.

Woods Hole MA 02543-1598 (508) 548-8700 x2226 (508) 457-2310 wbaldwin@usgs.gov Added keywords section with USGS persistent identifier as theme keyword. 20200806 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov 0.000001 0.000001 decimal degrees WGS 1984 WGS 84 6378137.0 298.257224 2017-001-FA_ROVUSBLNavPoints.shp ROV dive USBL point navigation shapefile for survey 2017-002-FA (1068 point features). U.S. Geological Survey FID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. Esri Coordinates defining the features. East Easting coordinate in UTM Zone 18 N meters, WGS 84 U.S. Geological Survey 546562.92 603393.29 meters .01 North Northing coordinate in UTM Zone 18 N meters, WGS 84 U.S. Geological Survey 4080574.37 4211757.48 meters .01 Lon Longitude coordinate in decimal degrees, WGS 84 U.S. Geological Survey -74.477562 -73.821625 degrees 1E-06 Lat Latitude coordinate in decimal degrees, WGS 84 U.S. Geological Survey 36.869959 38.047653 degrees 1E-06 DiveOp Name of the ROV dive represented by the trackline in the format: Dive # - Location (i.e.'Dive 3 - Norfolk East Arm'). U.S. Geological Survey Character set Year Year the data were collected YYYY. U.S. Geological Survey Character set JD_UTC Julian day and UTC time of navigation record in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. U.S. Geological Survey Character set SurveyID WHCMSC field activity identifier (e.g. "2017-001-FA" where 2017 is the survey year, 001 is survey number of that year, and FA is Field Activity). U.S. Geological Survey Character set VehicleID Survey vessel name. U.S. Geological Survey Character set RovID Remotely operated vehicle name. U.S. Geological Survey Character set DeviceID Ultra-short baseline device used to track the ROV. U.S. Geological Survey Character set 2017-001-FA_ROVUSBLTracklines.shp ROV dive USBL trackline navigation shapefile for survey 2017-001-FA (4 polyline features). U.S. Geological Survey FID Internal feature number. Esri Sequential unique whole numbers that are automatically generated. Shape Feature geometry. Esri Coordinates defining the features. DiveOp Name of the ROV dive represented by the trackline in the format: Dive # - Location (i.e.'Dive 3 - Norfolk East Arm'). U.S. Geological Survey Character set Year Calendar year the data were collected U.S. Geological Survey Character set JDUTC_init Julian day and UTC time at the start of the ROV dive in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. U.S. Geological Survey Character set JDUTC_end Julian day and UTC time at the end of the ROV dive in the format: JD:HH:MM:SS; Julian day is the integer number (although recorded here in text string format) representing the interval of time in days since January 1 of the year of collection. U.S. Geological Survey Character set SurveyID WHCMSC field activity identifier (e.g. "2017-001-FA" where 2017 is the survey year, 001 is survey number of that year, and FA is Field Activity). U.S. Geological Survey Character set VehicleID Survey vessel name. U.S. Geological Survey Character set RovID Remotely operated vehicle name. U.S. Geological Survey Character set DeviceID Ultra-short baseline device used to track the ROV. U.S. Geological Survey Character set Length_km Length of dive trackline in kilometers (UTM Zone 18N, WGS 84) calculated using XTools Pro. U.S. Geological Survey 2.45 11.82 kilometers 0.01 Compilation of edited USBL point and trackline navigation for ROV Global Explorer dives conducted during USGS field activity 2017-001-FA. U.S. Geological Survey U.S. Geological Survey - ScienceBase mailing and physical address

Denver Federal Center

Building 810

Mail Stop 302

Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov USGS data release of USBL point and trackline navigation for ROV Global Explorer dives conducted along the U.S. Atlantic continental shelf break and upper slope between Baltimore and Keller Canyons during USGS field activity 2017-001-FA: includes '2017-001-FA_ROVUSBLNavPoints.shp' containing the edited point navigation features, '2017-001-FA_ROVUSBLTracklines.shp' containing the trackline features, the browse graphic 2017-001-FA_ROVUSBLNav_browse.jpg, and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file '2017-002-FA_ROVUSBLNav_meta.xml'. These datasets can be downloaded individually or packaged on-demand in a zip file (see the Digital Transfer Option section). Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Shapefile ArcMap 10.7.1 Shapefile Shapefile of ROV USBL trackline navigation collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center along the U.S. Atlantic continental shelf break and upper slope between Baltimore and Keller Canyons during field activity 2017-001-FA and the associated metadata. none 1.2 https://www.sciencebase.gov/catalog/item/5e28b586e4b0d3f93b05fe2b https://www.sciencebase.gov/catalog/file/get/5e28b586e4b0d3f93b05fe2b https://doi.org/10.5066/P9Y1MSTN The first link is to the page containing the data. The second is a direct link to download all data available from the page as a zip file. The final link is to the publication landing page. The data page (first link) may have additional data access options, including web services. Shapefile ArcMap 10.7.1 Shapefile Shapefile of ROV USBL point navigation collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center along the U.S. Atlantic continental shelf break and upper slope between Baltimore and Keller Canyons during field activity 2017-001-FA and the associated metadata. none 1.7 https://www.sciencebase.gov/catalog/item/5e28b586e4b0d3f93b05fe2b https://www.sciencebase.gov/catalog/file/get/5e28b586e4b0d3f93b05fe2b https://doi.org/10.5066/P9Y1MSTN The first link is to the page containing the data, the second link downloads all data available from the page as a zip file, and the third link is to the publication landing page. none To utilize these data, the user must have software capable of reading shapefiles. 20240319 U.S. Geological Survey Wayne E. Baldwin Geologist mailing and physical

384 Woods Hole Rd.

Woods Hole MA 02543-1598 (508) 548-8700 x2226 (508) 457-2310 whsc_data_contact@usgs.gov The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319) FGDC Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 local time