Wayne E. Baldwin 20260521 1.0 Shapefile, CSV, PNG Image, SEG-Y data release DOI:10.5066/P14NWTX8 Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://doi.org/10.5066/P14NWTX8 https://www.sciencebase.gov/catalog/item/68b08553d4be021f0facf2cb Brian D. Andrews Wayne E. Baldwin Seth D. Ackerman Charles R. Worley Eric M. Moore Alex R. Nichols Patrick J. Berube Emily C. Huntley Laura L. Brothers 2026 1.0 data release DOI:10.5066/P14NWTX8 Reston, VA U.S. Geological Survey Suggested citation: Andrews, B.D., Baldwin, W.E., Ackerman, S.D., Worley, C.R., Moore, E.M., Nichols, A.R., Berube, P.J., Huntley, E.C., and Brothers, L.L., 2026, High-resolution geophysical and sampling data collected in Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P14NWTX8 https://doi.org/10.5066/P14NWTX8 https://www.sciencebase.gov/catalog/item/68adc403d4be027f635b3f90 In May and June 2023, the U.S. Geological Survey, in collaboration with the Massachusetts Office of Coastal Zone Management, collected high-resolution geophysical and seafloor sampling data, in Nantucket Sound to understand the regional geology in the vicinity of Horseshoe Shoal. 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. In addition to resolving coastal hazards, habitats and resources, these data can be used to better understand the Quaternary history of coastal Massachusetts including the influence of sea-level change and sediment supply on coastal evolution. This collaboration produces high-resolution geologic 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 Reports and Data Releases https://www.usgs.gov/centers/whcmsc/science/geologic-mapping-massachusetts-seafloor. This dataset contains shotpoint and trackline navigation, profile images, and processed SEG-Y trace data for approximately 400 km of EdgeTech 3400 chirp seismic-reflection data collected by the U.S. Geological Survey during USGS field activity 2023-001-FA in Nantucket Sound. Images of each seismic profile were generated in order to provide portable and easily viewable alternatives to the SEG-Y versions of the data. Each profile image can be hyperlinked to its corresponding trackline navigation contained within the Esri polyline shapefile '2023-001-FA_ET3400_Tracklines.shp'. Shotpoint index and tick marks along the top of the PNG images correlate to the positions of 500 shot intervals within the Esri point shapefile '2023-001-FA_ET3400_sht500.shp'. This information allows for spatial correlation of chirp seismic-reflection profiles images with other geophysical and sample data for investigating sea-floor morphology and stratigraphy in the area. Support for 2023-001-FA was provided to the USGS from the Massachusetts Office of Coastal Zone Management. Approximately 441 linear kilometers of multibeam echosounder data, 400 km of seismic reflection profiling data were collected during 8 survey days along tracklines spaced 87 or 52 meters apart. Part 2 of this survey included ground validation using SEABOSS imagery and sediment samples collected at 59 stations covering both the 2022-001-FA and 2023-001-FA survey area. Data were collected using the R/V Rafael, owned and operated by the USGS Woods Hole Coastal and Marine Science Center. Additional information on both the 2022 and 2023 field activities are available from https://cmgds.marine.usgs.gov/services/activity.php?fan=2022-001-FA, https://cmgds.marine.usgs.gov/services/activity.php?fan=2023-001-FA 20230601 20230611 ground condition Complete None planned -70.481647 -70.324562 41.584612 41.525928 ISO 19115 Topic Category location geoscientificInformation oceans 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 Massachusetts Office of Coastal Zone Management CZM MassCZM field activity number 2023-001-FA R/V Rafael shapefile trackline navigation seismic navigation seismic reflection seismic profile SEG-Y traces chirp EdgeTech 3400 image PNG USGS Thesaurus seismic reflection methods sub-bottom profiling marine geophysics marine geology navigational data geospatial datasets USGS Metadata Identifier USGS:68b08553d4be021f0facf2cb None United States of America Massachusetts Atlantic Ocean Atlantic Margin Nantucket Sound Horseshoe Shoal Eldridge Shoal Succonnesset Shoal Wreck Shoal None sea floor seafloor none 2023 No access constraints. Please see 'Distribution Information' for details. These data are marked with a Creative Commons CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Wayne Baldwin U.S. Geological Survey 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/68b08553d4be021f0facf2cb?name=2023-001-FA_ET3400_browse.jpg Thumbnail image showing the extent of chirp seismic-reflection profile data collected within Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA. JPEG Norris, M.W. Faichney, A.K. 2002 document Tulsa, OK Society of Exploration Geophysicists https://seg.org/wp-content/uploads/2025/11/seg_y_rev1.pdf Brian D. Andrews Wayne E. Baldwin Charles R. Worley Eric M. Moore Alex R. Nichols William W. Danforth David S. Foster Seth D. Ackerman Laura L. Brothers 2023 1.0 data release DOI:10.5066/P9O5G5OT Reston, VA U.S. Geological Survey This previous data release was also published as part of the USGS/CZM cooperative and may be of interest to others because it is directly south of, and overlaps, with the data collected during USGS Field Activity 2023-001-FA. https://doi.org/10.5066/P9O5G5OT Baldwin, W.E. Foster, D.S. Barnhardt., W.A. Schwab, W.C. Andrews, B.D. Ackerman, S.D. 2016 Open-File Report 2016-1119 Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program https://doi.org/10.3133/ofr20161119 Pendleton, E.A. Andrews, B.D. Ackerman, S.D. Danforth, W.W. Foster, D.S. 2014 Open-File Report 2013–1020 Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program https://doi.org/10.3133/ofr20131020 Andrews, B.D. Ackerman, S.D. Baldwin, W.E. Foster, D.S. Schwab, W.C. 2013 Open-File Report 2012–1006 Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Geology Program https://doi.org/10.3133/ofr20121006 Chirp seismic-reflection data were collected on the following dates: 20230601-20230602 (Julian day 152-153), 20220606-20220611 (Julian day 157-162). '2023-001-FA_ET3400_sht500.shp' contains the first, last, and 500-interval shotpoints for each seismic trackline, and '2023-001-FA_ET3400_shtnav.csv' contains all unique shot point navigation. The attribute fields 'LineName' and 'ImageName' for each polyline feature in '2023-001-FA_ET3400_Tracklines.shp' correspond to the SEG-Y data files in '2023-001-FA_ET3400_Segy.zip' and the PNG profile images in "2023-001-FA_ET3400_Images.zip", respectively. One SEG-Y file, and PNG image exists for each feature. Processed seismic data were converted to PNG format for ease of seismic trace display. Quality control was conducted during processing. Sections of tracklines where navigation was recorded but no seismic data were logged are not included such as during testing, some turns, and very short files. The EdgeTech 3400 subbottom profiler was towed from the port side davit of the R/V Rafael. The towfish was suspended ~ 1 m below the water line from a catamaran float, and towed approximately 13 meters astern of the DGPS antenna mounted on the after end of the cabin while underway. Navigation data for the 3400 were collected using a Hemisphere DGPS receiver, and layback positioning of the towfish relative to the GPS antenna was calculated during processing. Positioning data were recorded using EdgeTech Discover Subbottom SBP (version 41.0.1.116) acquisition software, which logged coordinates to individual trace headers in JSF and SEG-Y format. During line 20230601_152830 the navigation feed to Discover was interrupted or provided spurious coordinates, in these instances position and time were derived from the Hypack raw files and merged with the traces during processing. DGPS horizontal positional accuracy is assumed to be within 3 m, but due to uncertainty associated with layback correction we assume a more conservative positional accuracy of within 13 m. U.S. Geological Survey unpublished material digital data disc 20230601 20230611 ground condition JSF 3400 chirp data The EdgeTech 3400 subbottom profiler was towed from the port side davit of the R/V Rafael. The towfish was suspended ~ 1 m below the water line from a catamaran float and towed approximately 13 meters astern of the DGPS antenna mounted on the after end of the cabin while underway. Chirp seismic data were collected using the EdgeTech 3400 sub-bottom profiling system topside acquisition and towfish. EdgeTech Discover Subbottom (version 41.0.1.116) seismic acquisition software was used to control the topside unit, digitally log three trace data (envelope, real, and imaginary) in the JSF and SEG-Y Rev. 1 (IEEE floating point) formats, and record DGPS navigation coordinates to the trace headers (in arc seconds of Latitude and Longitude, multiplied by a scalar of 100). JSF files contain header values for latitude, longitude, ffid, year, Julian Day, UTC time, and towfish heave, pitch, roll, and pressure depth. Data were acquired using 25-ms shot rates, a 20-ms pulse length, and a 3 to 12 kHz frequency sweep. Traces were recorded with a 20-microsecond sample interval and trace lengths of 100 ms. PROCESS STEP 1: NAVIGATION EXTRACTION, TOWFISH LAYBACK CALCULATION, RAW TRACE IMPORT jsf2segy (version 5) and a iPython jupyter notebook, and Shearwater Reveal (version 2023) were used to process JSF data, extract navigation data, and calculate towfish layback position. The processing flows are summarized in the following steps. (1.) ‘jsf2segy’ was used to create SEG-Y files containing the real chirp traces from the JSF files. Option '-x' extracted real values from Analytic subbottom data, '-o' allowed writing real traces to an output .sgy file, and '-c' allowed writing a comma separated values (csv) file containing a JSF header values for latitude, longitude, ffid, year, Julian day, UTC time and towfish heave, pitch, roll, and pressure depth for use in additional processing. (2.) The output header csv files for each profile line were inspected for erroneous or absent navigation data. Profile line 20230601_152830 contained a section of missing navigation due to interruption of the GPS feed to Discover. A python Jupyter notebook utilized the python modules pandas (version 1.5.2), geopandas (version 0.12.1), pyproj (version 3.4.0), numpy (version 1.23.5), shapely (version 1.8.5.post1), and sqlite3 (version 3.40.0) to process the navigation data for each profile line in the following steps. The csv file was imported to a pandas dataframe. Appropriate time periods were extracted from Hypack raw files and merged by UTC time into the pandas dataframe of files with missing navigation sections. Navigation coordinates repeated over many traces because the DGPS sampling frequency was 1-Hz, while the chirp shot rate was 4-Hz. To account for this, duplicate latitude and longitude coordinate pairs in the dataframe were replaced by NAN values, while maintaining the first occurrence of a unique pair, as well as the last unique pair. The NAN values were replaced by coordinate pairs calculated through linear interpolation between the remaining unique pairs, resulting in unique navigation for every trace. The python function ShotlineLayback (developed by Nathan Miller of USGS-WHCMSC) computed layback navigation coordinates for the 3400 towfish. The algorithm used pyproj to transform the navigation reference point (nrp) coordinates from geographic (decimal degrees) to WGS84 UTM Zone 19 (meters), interpolated a sail line from the nrp coordinates along with a cumulative distance value, then computed layback positions for the 3400 shots by translating the nrp coordinates back along the sail line by the associated GPS to towfish offset value, and finally transformed the calculated layback UTM 19 coordinates back to geographic and wrote both set of coordinates to new data frame columns. A subset of the resulting dataframe consisting of values for layback easting and northing, layback latitude and longitude, profile line name, shot, UTC date/time, nrp longitude and latitude, as well as new fields populated for profile image name, survey ID, vehicle ID, and device ID was generated. The subset dataframe was written to a new 'layback-nav' csv file to be used in additional trace processing, then Geopandas and shapely were used to create a point geometry column from the layback geographic coordinates. SQL queries were used to load the navigation dataframe into a geospatial SQLite database using the pyspatialite interface. Records were appended to three database tables, the first containing the unique shot navigation, the second maintaining the first and last shots and even 500 shot intervals (which correspond to the annotation interval provided along the top of the seismic-reflection profile images), and the third containing trackline features created from the unique layback navigation point geometries. (3.) The Reveal flow ImportSegy consisted of the following steps for each seismic file. Input imported the raw real segy traces. DBMerge imported nrp and layback navigation from the 'layback-nav' csv file using the ffid field to merge. HeaderMath converted towfish depth in meters to milliseconds and heave in seconds to milliseconds. Header Filtering smoothed the towfish depth time series using a 31 trace boxcar filter. ApplyStatic shifted the traces by the smoothed towfish depth and heave static values. ObspyPicking used the threshold algorithm to predict the seafloor time and Header2Picks wrote the times to an output csv file for editing. Output wrote the traces to .seis (Reveal’s format) files for additional processing. These process steps and all subsequent process steps were conducted by the same person - Wayne Baldwin. 202410 Raw real trace seis files, nrp-nav csv files, seafloor time pick tables. U.S. Geological Survey Wayne 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 PROCESS STEP 2: NAVIGATION FEATURE CLASS GENERATION. The 500 shot and trackline tables were imported into QGIS (version 3.26) from the SQLite database, then exported (Right click on database feature class > Data > Save Features As) to the new Esri point and polyline shapefiles '2023-001-FA_ET3400_sht500.shp' and '2023-001-FA_ET3400_Tracklines.shp', respectively. 202410 layback-nav csv files, navigation database tables, navigation feature classes. PROCESS STEP 3: SEAFLOOR PICK EDITS, FINAL TRACE PROCESSING (1.) Using the Reveal 2D profile viewer, the seafloor predictions generated in step one were overlain on their associated seismic traces for quality control. The pick editor was used to eliminate or appropriately adjust erroneous times and edits were saved. (2.) The Reveal flow GainSegy consisted of the following steps for each seismic file. Input imported the raw real .seis file. Table2Header imported the edited seafloor picks replacing unedited header values. TraceMath applied a time varying gain to trace samples after the seafloor time (trace sample = trace sample * (trace sample time * 1000) ^ 0.7), and muted trace samples before the seafloor time. Output wrote the processed real traces to seis and SEG-Y files. Complex Trace Analysis (CTAN) computed envelope traces from the real, and finally Output wrote the processed envelope traces to seis and SEG-Y file. 202410 edited seafloor time pick tables, processed real and envelope seis and segy trace files. PROCESS STEP 4: DIAGNOSTIC SEISMIC PROFILE PLOTTING The Seismic Unix script PlotChirp created variable density postscript plots of the seismic profiles showing two-way travel time (seconds) along the y-axis (left margin) and shots along profile (labeled at 500 shot intervals) on the x-axis (along top of profile). The postscript images were converted to 150 dpi portable network graphic (PNG) images using ImageMagick (version 6.9.11-60). The plots are labeled along the bottom of the X axis. 202410 PNG profile plots. 0.000001 0.000001 Decimal degrees WGS 1984 WGS 84 6378137.0 298.257224 2023-001-FA_ET3400_Tracklines.shp ET3400 Trackline shapefile for survey 2023-001-FA (98 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. LineName Name of the trackline along which seismic-reflection data were collected in the format: Date and UTC time of file initiation time, as follows YYYYMMDD_HHMMSS (e.g.'20230601_134203'). U.S. Geological Survey Character set ImageName PNG image name of seismic-reflection profile corresponding to survey trackline using the same naming convention as the attribute LineName. U.S. Geological Survey Character set Shot_init Shot number at the start of the survey line. U.S. Geological Survey 1 1 shot 1 Shot_end Shot number at the end of the survey line. U.S. Geological Survey 518 10567 shot 1 Date Calendar month, day, and year at start of line as a text string in the format: MM/DD/YYYY. U.S. Geological Survey Character set UTCDT_init Year, Julian day, and UTC time at the start of the survey line in the format: YYYY: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 UTCDT_end Year, Julian day, and UTC time at the end of the survey line in the format: YYY: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., "2023-001-FA" where 2023 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 DeviceID Sonar device used to collect seismic-reflection data. U.S. Geological Survey Character set Length_km Length of seismic-reflection data line in kilometers (UTM Zone 19N, WGS 84) calculated in the SQLite database. U.S. Geological Survey 0.366 8.216 kilometers 0.001 2023-001-FA_ET3400_sht500.shp ET3400 500-interval shot point shapefile for survey 2023-001-FA (1186 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 19 N meters, WGS 84 U.S. Geological Survey 376419.33 389521.07 meters .01 North Northing coordinate in UTM Zone 19 N meters, WGS 84 U.S. Geological Survey 4598075.82 4604560.01 meters .01 Lon Longitude coordinate in decimal degrees, WGS 84 U.S. Geological Survey -70.481647 -70.324562 degrees 1E-06 Lat Latitude coordinate in decimal degrees, WGS 84 U.S. Geological Survey 41.525928 41.584612 degrees 1E-06 LineName Name of the trackline along which seismic-reflection data were collected in the format: Date and UTC time of file initiation time, as follows YYYYMMDD_HHMMSS (i.e.'20230601_134203'). U.S. Geological Survey Character set ImageName PNG image name of seismic-reflection profile corresponding to survey line using the same naming convention as the attribute LineName. U.S. Geological Survey Character set Shot Shot number (values are first, last, and every 500 shot between). U.S. Geological Survey 1 10567 shot 1 Date Calendar month, day, and year at start of line as a text string in the format: MM/DD/YYYY. U.S. Geological Survey Character set UTC_DT Year, Julian day, and UTC time for first, last, and every 500 shot point between of the survey line in the format: YYYY: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. "2023-001-FA" where 2023 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 DeviceID Sonar device used to collect seismic-reflection data. U.S. Geological Survey Character set NRP_Lon The longitude coordinate in decimal degrees, WGS 84 of the navigation reference point (GPS antenna) U.S. Geological Survey -70.481690 -70.324460 degrees 1E-06 NRP_Lat The latitude coordinate in decimal degrees, WGS 84 of the navigation reference point (GPS antenna) U.S. Geological Survey 41.525840 41.584517 degrees 1E-06 2023-001-FA_ET3400_shtnav.csv ET3400 shot point comma separated values file for survey 2023-001-FA (521554 point features). U.S. Geological Survey 2023-001-FA_ET3400_Images Portable network graphic images of processed ET3400 profiles for survey 2023-001-FA (98 PNG images). U.S. Geological Survey 2023-001-FA_ET3400_SegyData SEG-Y format files of processed SB512i profiles for survey 2023-001-FA (98 SEG-Y files). U.S. Geological Survey The column headings and range domain values in '2023-001-FA_ET3400_shtnav.csv' match those in '2023-001-FA_ET3400_sht500.shp'. The PNG seismic reflection images can be hyperlinked to their corresponding trackline or shotpoint locations in a GIS using the shapefiles '2023-001-FA_ET3400_Tracklines.shp' or '2023-001-FA_ET3400_sht500.shp', respectively. The fist, last, and multiple of 500 shot features in '2023-001-FA_ET3400_sht500.shp' correspond to the x-axis ticks on the PNG images, which show two-way travel time (seconds) on the y-axis and distance along profile (annotation at 500 shot intervals) on the x-axis. The names of segy files included in 2023-001-FA_ET3400_SEG-Y.zip have the string 'proc-env' inserted between the profile line name and the .sgy extension to indicate that the files contain the processed envelope version of the traces. 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 EdgeTech 3400 chirp seismic-reflection data collected within Nantucket Sound Massachusetts in the vicinity of Horseshoe Shoal, during USGS Field Activity 2023-001-FA: includes '2023-001-FA_ET3400_sht500.shp' containing the first, last and 500-interval shotpoint locations, '2023-001-FA_ET3400_shtnav.csv' containing unique shot point locations, '2023-001-FA_ET3400_Tracklines.shp' containing trackline features, '2023-001-FA_ET3400_Images.zip' containing 98 PNG images named according to line convention, '2023-001-FA_ET3400_SegyData.zip' containing 98 SEG-Y files of the processed traces, the browse graphic 2023-001-FA_ET3400_browse.jpg, and Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file '2023-001-FA_ET3400_meta.xml'. These datasets can be downloaded individually (see the Digital Transfer Option section). 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 for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Shapefile QGIS 3.34.8 Shapefile Zip compressed folder "2023-001-FA_ET3400_Data.zip" containing shapefiles of ET3400 shotpoints and tracklines collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center in Nantucket Sound, Massachusetts during USGS Field Activity 2023-001-FA and the associated metadata. To utilize these data, the user must have software capable of uncompressing the zip file and reading shapefile format, or GIS software. 4.7 https://www.sciencebase.gov/catalog/file/get/68b08553d4be021f0facf2cb?name=2023-001-FA_ET3400_Data.zip https://www.sciencebase.gov/catalog/item/68b08553d4be021f0facf2cb https://doi.org/10.5066/P14NWTX8 The data can be downloaded using the Network Resource Name links. The first link is to a direct download of the zipped file of data. The second and third links are to a landing page for the entire data release where the data, metadata, and browse graphic can be downloaded. CSV none Comma-Separated Values (CSV) Zip compressed folder "2023-001-FA_ET3400_shtnav.zip" containing a CSV file of ET3400 unique shotpoints collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center in Nantucket Sound, Massachusetts during USGS Field Activity 2023-001-FA and the associated metadata. The CSV file can be viewed with any text editor or spreadsheet software. 11.4 https://www.sciencebase.gov/catalog/file/get/68b08553d4be021f0facf2cb?name=2023-001-FA_ET3400_shtnav.zip https://www.sciencebase.gov/catalog/item/68b08553d4be021f0facf2cb https://doi.org/10.5066/P14NWTX8 The data can be downloaded using the Network Resource Name links. The first link is to a direct download of the zipped file of data. The second and third links are to a landing page for the entire data release where the data, metadata, and browse graphic can be downloaded. PNG ImageMagick (version 6.9.11-60) Portable Network Graphic (PNG) Zip compressed folder "2023-001-FA_ET3400_Images.zip" containing ET3400 seismic reflection profile images collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center in Nantucket Sound, Massachusetts during USGS Field Activity 2023-001-FA and the associated metadata. Use any zip decompression utility to uncompress the image folder. The PNG files can be viewed with any image viewing software. 562.7 https://www.sciencebase.gov/catalog/file/get/68b08553d4be021f0facf2cb?name=2023-001-FA_ET3400_Images.zip https://www.sciencebase.gov/catalog/item/68b08553d4be021f0facf2cb https://doi.org/10.5066/P14NWTX8 The data can be downloaded using the Network Resource Name links. The first link is to a direct download of the zipped file of data. The second and third links are to a landing page for the entire data release where the data, metadata, and browse graphic can be downloaded. SEG-Y SEG-Y Rev. 1 SEG-Y Zip compressed folder "2023-001-FA_ET3400_Segy.zip" containing processed ET3400 seismic reflection trace data collected by the U.S. Geological Survey - Woods Hole Coastal and Marine Science Center during USGS Field Activity 2023-001-FA and the associated metadata. Use any zip decompression utility 8042.1 https://www.sciencebase.gov/catalog/item/68b08553d4be021f0facf2cb?name=2023-001-FA_ET3400_Segy.zip https://www.sciencebase.gov/catalog/item/68b08553d4be021f0facf2cb https://doi.org/10.5066/P14NWTX8 The data can be downloaded using the Network Resource Name links. The first link is to a direct download of the zipped file of data. The second and third links are to a landing page for the entire data release where the data, metadata, and browse graphic can be downloaded. none To utilize these data, the user must have software capable of reading shapefiles, CSV files, PNG images, and/or SEG-Y seismic trace files. 20260521 U.S. Geological Survey Wayne 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 the USGS. Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998 local time