Daniel S. Brothers Neal W. Driscoll Graham M. Kent Robert L. Baskin Alicia F. Balster-Gee 20220322 seismic-reflection data in SEG-Y format data release DOI:10.5066/P9ER5TNT Pacific Coastal and Marine Science Center, Santa Cruz, California U.S. Geological Survey https://doi.org/10.5066/P9ER5TNT More than 1,000 line-km of sub-bottom chirp data were collected with an Edgetech 0.5-16 kHz subscan system by Scripps Institution of Oceanography between 2006 and 2008 in the Salton Sea, California, with assistance from the U.S. Geological Survey (USGS). Data were subsequently donated by Scripps to the USGS for public release (USGS field activity identifier 2006-603-DD). The Salton Sea is a large, shallow lake located in the central Salton Trough of Southern California that covers the southernmost extension of the San Andreas Fault (SAF) and the northernmost transtensional step-over associated with Gulf of California oblique rifting. Seismic hazard assessments require regional studies that account for rupture along secondary faults and their potential to inhibit or promote failure on the SAF. Therefore, understanding the kinematic relationships and seismic cycling between the SAF and extensional faults beneath the Salton Sea is of utmost importance. The data in this report were acquired to better understand the late-Holocene depositional framework and deformation history within the submerged portion of the San Andreas-Imperial Fault pull-apart basin, and to examine coseismic deformation preserved in Lake Cahuilla sediments. Previously published articles (for example, Brothers and others, 2009; Brothers and others, 2011) used the sub-bottom chirp data included in this release to map numerous faults, to define the shallow basin architecture, and to estimate the timing of coseismic displacement across several faults. The Scripps Institution of Oceanography was the lead institution for this field activity; the data have been donated for public release. These data and information are intended for science researchers, students from elementary through college, policy makers, and the general public. Additional information about the field activity from which these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=2006-603-DD 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. 20060804 20080904 Ground condition at time data were collected Complete None planned -116.13977054 -115.55090312 33.57526889 33.06484469 USGS Metadata Identifier USGS:e2c46a75-a30a-45ab-a837-3f6b0344ac6c ISO 19115 Topic Category geoscientificInformation Data Categories for Marine Planning Substrate USGS Thesaurus sub-bottom profiling marine geophysics geospatial datasets Marine Realms Information Bank (MRIB) keywords seismic reflection profiling lake 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 California Niland Salton City Bombay Beach Mecca Brawley Salton Sea 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 Scripps Institution of Oceanography 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

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov SaltonSeaChirp_Map_2006-603-DD.png Map of chirp tracklines collected between 2006 and 2008 PNG California Department of Water Resources, California Department of Fish and Game, UCSD Academic Senate, Scripps Institution of Oceanography, Sonny Bono Salton Sea National Wildlife Refuge, National Science Foundation, and Southern California Earthquake Center SEGY Rev 1 Daniel S. Brothers Neal W. Driscoll Graham M. Kent A. J. Harding J. M. Babcock Robert L. Baskin 2009 Brothers, D., Driscoll, N., Kent, G., Harding, A.J., Babcock, J.M., and Baskin, R.L., 2009, Tectonic evolution of the Salton Sea inferred from seismic reflection data: Nature Geoscience, v. 2, p. 581–584, https://doi.org/10.1038/ngeo590. https://doi.org/10.1038/ngeo590 Daniel S. Brothers D. K. Klib K. Luttrell Graham M. Kent G. Lin Neal W. Driscoll 2011 Brothers, D., Kilb, D., Luttrell, K., Driscol, N., and Graham, K., 2011, Loading of the San Andreas fault by flood-induced rupture of faults beneath the Salton Sea: Nature Geoscience, v. 4, p. 486–492, https://doi.org/10.1038/ngeo1184. https://doi.org/10.1038/ngeo1184 Identified as the best available version. Subbottom data were collected between 2006 and 2008 by researchers from Scripps Institution of Oceanography aboard USGS Utah Water Science Center’s R/V Stevens using a custom Edgetech sub-bottom profiling system owned by the Scripps Institution of Oceanography. This system consists 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 water surface. The swept-frequency “chirp” source signal is between 500 and 16,000 Hz, and data are recorded by hydrophones located on the bottom of the fish. 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 Hemisphere V100 Global Positioning System using L1, C/A code and carrier phase smoothing with a stated accuracy of 60 centimeters. Depths shown in the seismic data files are in milliseconds (round trip travel time) and are referenced to sea level. The chirp seismic-reflection profiles were acquired with a swept-frequency source towed at about 3 meters below the sea surface. Data were recorded to Edgetech JSF format using Edgetech recording software. Survey speeds were approximately 4 knots. Sub-bottom surveys employed different chirp pulses depending on sub-bottom conditions. The 0.7 – 3.0 kHz, 50 ms pulse provided greatest penetration (up to 60 m) while the 1.0 – 15.0 kHz, 30 ms pulse produced the highest vertical resolution (~15 cm). Acquisition parameters for all SEG-Y files are recorded in the textual headers. 20080904 Correction was made to keywords. No data were changed. (scochran@usgs.gov) 20220525 Horizontal X and Y locations for the seismic profile locations are provided and stored in the SEG-Y data trace headers in header bytes 81 and 85 locations. WGS 1984 UTM Zone 11N 0.9996 -117.0 0.0 500000.0 0.0 coordinate pair 0.0001 0.0001 Meter D_WGS_1984 WGS_1984 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 - CMGDS mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov SaltonSea_chirp_2006-603-DD.zip contains high-resolution seismic-reflection (SEG-Y) data donated to PCMSC for public release by Scripps Institution of Oceanography. These data are divided up and presented by navigation line, as reflected in the individual file names. 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 21500 https://doi.org/10.5066/P9ER5TNT Data can be downloaded using the Network_Resource_Name link and scrolling down to the Seismic Data section. None. Use of SEG-Y data requires specialized software, such as ProMax and Seisworks by Landmark Geophysical; FOCUS and SeisX by Paradigm Geophysical; SPW by Parallel Geoscience; VISTA by Seismic Image Software; SeiSee by Dalmorneftegeophysica (DMNG); amongst others. 20220525 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