Alicia F. Balster-Gee Daniel S. Brothers James E. Conrad Jared W. Kluesner Patrick E. Hart Peter J. Haeussler 2017 chirp seismic-reflection data in SEG-Y format data release DOI:10.5066/F7RX9B1R Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey https://doi.org/10.5066/F7RX9B1R https://www.sciencebase.gov/catalog/item/59e7d913e4b05fe04cd3a45a?name=2015-651-FA_chirp.zip Alicia F. Balster-Gee Daniel S. Brothers James E. Conrad Jared W. Kluesner Patrick E. Hart Peter J. Haeussler 2017 data release DOI:10.5066/F7RX9B1R Pacific Coastal and Marine Science Center, Santa Cruz, CA U.S. Geological Survey https://doi.org/10.5066/F7RX9B1R This data release contains high-resolution seismic reflection data collected in August of 2015 to explore marine geologic hazards of inland waterways of southeastern Alaska. Sub-bottom profiles were acquired in the inland waters between Glacier Bay and Juneau, including Cross Sound and Chatham Strait. High-resolution seismic-reflection profiles were acquired to assess evidence for active seabed faulting and submarine landslide hazards. The data were collected aboard the US Geological Survey R/V Alaskan Gyre. The seismic-reflection data were acquired using a tow-fish Edgetech 512 chirp subbottom profiler. Subbottom acoustic penetration spans up to several tens of meters, and is variable by location. This data release contains processed digital SEG-Y. This data release will be updated as subsequent lines of data from this field activity are published. The U.S. Geological Survey (USGS) collected high-resolution chirp seismic-reflection data in August of 2015, in the inland waterways between Glacier bay and Juneau including Chatham Strait and Cross Sound, in southeastern Alaska. The survey was designed to identify the spatial distribution of active faults, assess the regional evidence for active seabed faulting, and identify submarine landslide hazards. These data can be used to better image and understand the deformation history and earthquake/tsunami hazards of the Queen Charlotte-Fairweather fault system, a major plate boundary strike-slip fault system that accommodates more than ninety percent of the relative motion between the Pacific and North American plates. In addition, the survey images submarine landslides in these inland waterways of southeastern Alaska in order to determine causes and age of seafloor failure. This work was funded by the USGS Coastal and Marine Geology Program’s Marine Geohazards Project and the Alaska Department of Fish and Game (ADFG). The high-resolution seismic-reflection profiles of bedrock, sediment deposits and tectonic structure provide geologic information that is essential to hazard assessment, regional sediment management and coastal and marine spatial planning at Federal, State and local levels, as well as to future research on the geomorphic, sedimentary, tectonic and climatic record of southeastern Alaska. Additional information about the field activity from which these data were derived is available online at: http://cmgds.marine.usgs.gov/fan_info.php?fan=2015-651-FA Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. 20150803 20150821 ground condition at the time the data were collected In work As needed -153.457 -133.404 58.4340 52.2441 USGS Metadata Identifier USGS:59e7d913e4b05fe04cd3a45a Global Change Master Directory (GCMD) Bathymetry Continental Margins ISO 19115 Topic Category geoscientificInformation oceans USGS Thesaurus sub-bottom profiling Marine Realms Information Bank (MRIB) keywords seismic reflection profiling Data Categories for Marine Planning Bathymetry and Elevation None chirp U.S. Geological Survey USGS Coastal and Marine Geology Program CMG CMGP Pacific Coastal and Marine Science Center PCMSC Geographic Names Information System (GNIS) Pacific Ocean State of Alaska Juneau Glacier Bay Cross Sound Chatham Strait Lynn Canal 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 as the originator(s) of the dataset and in products derived from these data. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. This information is not intended for navigational 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/59e7d913e4b05fe04cd3a45a?name=2015-651-FA_chirp_index_map.jpg&allowOpen=true index map JPEG SEG-Y Rev 1 Identified as best available version. Subbottom data were collected during USGS cruise 2015-651-FA using a tow-fish Edgetech 512 chirp subbottom profiler. Quality control was conducted during the collection process. 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. Position data were provided by a Differential Global Positioning System (DGPS) navigation receiver. Depths shown in the seismic data files are in milliseconds (round trip travel time) and are referenced to sea level. Seismic-reflection data were collected using a tow-fish Edgetech 512 chirp subbottom profiler consisting of a source transducer and an array of receiving hydrophones housed in a 500-lb “fish” towed at a depth of several meters below the sea surface. The swept-frequency “chirp” source signal is approximately 500 – 4,500 Hz, and data are recorded by hydrophones located on the bottom of the fish. The data consist of three-channels: a raw channel, a 90-degree phase-shifted channel, and an “amplitude envelop” channel created and transformed internally from the other two channels. The data were recorded in standard SEG-Y 2015 Corrected author's middle initial from James R. Conrad to James E. Conrad in both the Citation and Larger Work Citation. No data were changed. 20200831 Susan A Cochran U.S. Geological Survey, Pacific Coastal and Marine Science Center mailing and physical

2885 Mission St.

Santa Cruz CA 95060 United States 831-460-7545 scochran@usgs.gov Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. 20201019 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 Performed minor edits to the metadata to correct typos. No data were changed 20211013 U.S. Geological Survey Susan A. Cochran Geologist Mailing and Physical

2885 Mission Street

Santa Cruz CA 95060 831-460-7545 scochran@usgs.gov Horizontal X and Y locations for the seismic profile locations are provided in ASCII position files and are stored in the SEG-Y data trace headers in the standard header locations. 0.00001 0.00001 Decimal degrees D_WGS_84 WGS_84 6378137.0 298.257223563 Local surface 0.1 meters Attribute values Navigation and Seismic Shots with Time Stamp in standard SEG-Y file format Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards 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 2015-651-FA_chirp.zip – zip file containing high-resolution seismic-reflection (SEG-Y) data collected during PCMSC field activity 2015-651-FA. The data are divided up and presented by navigation line, as reflected in the individual file name(s). 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. SEG-Y SEG-Y rev 1 Zip file contains the raw seismic data per navigation line Winzip, 7-zip, or Winrar are free software that will open .zip files 503 https://www.sciencebase.gov/catalog/file/get/59e7d913e4b05fe04cd3a45a?name=2015-651-FA_chirp.zip https://doi.org/10.5066/F7RX9B1R None 20211013 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