Metadata: Identification_Information: Citation: Citation_Information: Originator: Ray W. Sliter Originator: James E. Conrad Originator: Thomas D. Lorenson Originator: Antoinette G. Papesh Originator: Jonathan A. Warrick Publication_Date: 2021 Title: High-resolution, chirp seismic-reflection data collected offshore Oceanside to San Diego, southern California, during field activity 2018-638-FA from 2018-05-21 to 2018-05-26 Geospatial_Data_Presentation_Form: seismic-reflection data in SEG-Y format Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9690BEK Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P9690BEK Larger_Work_Citation: Citation_Information: Originator: Ray W. Sliter Originator: James E. Conrad Originator: Thomas D. Lorenson Originator: Antoinette G. Papesh Originator: Jonathan A. Warrick Publication_Date: 2021 Title: Geophysical and core sample data collected offshore Oceanside, southern California, during field activity 2018-638-FA from 2018-05-21 to 2018-05-26 Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9690BEK Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, CA Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/P9690BEK Description: Abstract: This part of the data release contains processed, high-resolution, chirp seismic-reflection profiles that were collected aboard the R/V Bold Horizon in 2018 on U.S. Geological Survey cruise 2018-638-FA offshore Oceanside to San Diego, southern California. Approximately 127 line-kilometers of chirp data were collected offshore Oceanside (BH lines) and 125 line-kilometers were collected offshore Silver Strand, San Diego (SS lines). The data were acquired using an Edgetech 512 Chirp sub-bottom profiling system. These data are divided up and presented by navigation line, as reflected in the individual file names. Purpose: The U.S. Geological Survey (USGS) collected high-resolution chirp seismic-reflection profiles in 2018 offshore Oceanside and San Diego, southern California. The goal of the chirp survey was to provide high-resolution imaging to characterize the surface and subsurface properties of the study area, including unconsolidated sediment thickness and subsurface sediment horizons. The along-shore and across-shore chirp profiles are oriented to assess sand and gravel resources in Federal and State waters for potential use in future beach nourishment projects along stretches of the coast where critical erosion hotspots have been identified. This cruise was funded through partnerships with the Bureau of Ocean Energy Management (BOEM) and the State of California Ocean Protection Council (OPC). Supplemental_Information: 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=2018-638-FA Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20180521 Ending_Date: 20180526 Currentness_Reference: ground condition at time data were collected Status: Progress: Planned Maintenance_and_Update_Frequency: As needed Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -117.63645 East_Bounding_Coordinate: -117.1887 North_Bounding_Coordinate: 33.36725 South_Bounding_Coordinate: 32.5307 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:184ce709-6b60-420e-a3f3-3c3607f27e2d Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: Substrate Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: sub-bottom profiling Theme_Keyword: marine geophysics Theme_Keyword: geospatial datasets Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords Theme_Keyword: seismic reflection profiling Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: CMHRP Theme_Keyword: Pacific Coastal and Marine Science Center Theme_Keyword: PCMSC Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Pacific Ocean Place_Keyword: State of California Place_Keyword: Oceanside Place_Keyword: San Mateo Point Place_Keyword: San Diego Place_Keyword: Silver Strand Place: Place_Keyword_Thesaurus: NGA GEOnet Names Server (GNS) Place_Keyword: North Pacific Ocean Access_Constraints: None Use_Constraints: 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 of the dataset and in products derived from these data. This information is not intended for navigation purposes. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: 2018-638-FA_tracks_and_cores.png Browse_Graphic_File_Description: Map showing locations of vibracore sites (purple dots) and tracklines (blue) along which chirp seismic data were collected. Browse_Graphic_File_Type: PNG Native_Data_Set_Environment: SEG-Y Rev Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Identified as best available version. The swell correction module output considerable anomalous static shift jumps due to horizontal amplitude variation at the seafloor that could not be improved upon due to time constrains. These lines are BH-02,03,06,14,15,16,19,20,21,22,23,24,25, and SS-02,05. The swell correction on these lines, however, was deemed adequate for interpretation purposes and were used for sand resource sediment thickness assessments. Other lines with smaller static breaks are BH-04a,04,05,07,18 and SS-04,06,08,09,11,13,14,16. Logical_Consistency_Report: Subbottom data were collected during USGS cruise 2018-638-FA using an Edgetech 512 Chirp sub-bottom profiling system. 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 sea surface. The swept-frequency “chirp” source signal is between 500 and 4,500 Hz, and data are recorded by hydrophones located on the bottom of the fish. Quality control was conducted during the collection process. Completeness_Report: 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. Equipment malfunction or shutdowns due to mammals in the area resulted in some lines having multiple parts. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: 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. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: Depths shown in the seismic data files are in milliseconds (round trip travel time) and are referenced to sea level. Delay value in header byte 109 has not been applied and should be applied for accurate display. Lineage: Process_Step: Process_Description: The chirp seismic-reflection profiles were acquired with a swept frequency source towed at about 5 meters depth below the sea surface and fired at roughly every 1 to 2 meters, depending on water depth. Data were recorded to Edgetech JSF format using Edgetech recording software. Survey speeds were approximately 4.5 knots. Process_Date: 20180526 Process_Step: Process_Description: Chirp seismic-reflection data were first converted from JSF to SEG-Y format. The SEG-Y files were then processed using Echos by Paradigm Geophysical. The following processing steps were applied to each line: 1)The fish depth header word was read and converted from millimeters to two-way travel time to create a fish-depth static value; 2) The fish depth static was applied to the data to correct for changing tow depth of Chirp fish; 3) an additional smoothing module was applied to the data to correct for the motion of the sea; and 4) final processed SEG-Y was output with correct navigation written to header bytes 81 and 85 in UTM coordinates. The scalar value for bytes 73 and 77, located in header byte 71 is incorrect, and the correct value is 1000. Delay value in header byte 109 has not been applied and should be applied for accurate display. These data are divided up and presented by navigation line, as reflected in the individual file names. Process_Date: 20190401 Spatial_Data_Organization_Information: Indirect_Spatial_Reference: 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 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: WGS 1984 UTM Zone 11N Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -117.0 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000.0 False_Northing: 0.0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.0001 Ordinate_Resolution: 0.0001 Planar_Distance_Units: Meter Geodetic_Model: Horizontal_Datum_Name: D WGS 1984 Ellipsoid_Name: WGS 1984 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257223563 Vertical_Coordinate_System_Definition: Depth_System_Definition: Depth_Datum_Name: Local surface Depth_Resolution: 0.1 Depth_Distance_Units: meters Depth_Encoding_Method: Attribute values Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: Navigation and seismic shots with Time Stamp in standard SEG-Y file format Entity_and_Attribute_Detail_Citation: Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey – Pacific Coastal and Marine Science Center Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 1-831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Resource_Description: 2018-638-FA_chirp_segy.zip contains high-resolution seismic-reflection (SEG-Y) data collected during PCMSC field activity 2018-638-FA. These data are divided up and presented by navigation line, as reflected in the individual file names. Distribution_Liability: 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. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: SEG-Y Format_Version_Number: SEG-Y rev 1 Format_Information_Content: Zip file contains the processed seismic data per navigation line File_Decompression_Technique: Winzip, 7-zip, or Winrar are free software that will open .zip files Transfer_Size: 3500 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.5066/P9690BEK Access_Instructions: Data can be downloaded using the Network_Resource_Name link, then scroll down to the Seismic Data section. Fees: None. Technical_Prerequisites: 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. Metadata_Reference_Information: Metadata_Date: 20210615 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998