Metadata: Identification_Information: Citation: Citation_Information: Originator: Travis Alongi Originator: Alicia F. Balster-Gee Originator: Jared W. Kluesner Originator: Ray W. Sliter Publication_Date: 20230809 Title: Reprocessed multichannel seismic reflection data acquired offshore Southern California during USGS field activity L-4-90-SC Geospatial_Data_Presentation_Form: seismic-reflection data in SEG-Y format Series_Information: Series_Name: data release Issue_Identification: DOI:10.5066/P9FOES4K Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California Publisher: U.S. Geological Survey Other_Citation_Details: Suggested Citation: Alongi, T., Balster-Gee, A.F., Kluesner, J.W., Sliter, R.W., 2023, Reprocessed multichannel seismic reflection data acquired offshore Southern California during USGS field activity L-4-90-SC: U.S. Geological Survey data release, https://doi.org/10.5066/P9FOES4K. Online_Linkage: https://doi.org/10.5066/P9FOES4K Description: Abstract: Multichannel seismic (MCS) data were collected by the U.S. Geological Survey (USGS) in 1990 in the California Continental Borderland (USGS field activity L490SC). In 2021 these data were reprocessed to improve accuracy and resolvability of geologic structures and fault systems of California’s continental margin. Purpose: MCS data were acquired to support the Southern California Earthquake Hazards project to help mitigate earthquake and tsunami hazards for the Southern California region by improving our understanding of how deformation is distributed (spatially and temporally) in the offshore with respect to the onshore region. The reprocessed dataset enhances the seismic data quality which will be useful for future research on the geomorphic, sedimentary and tectonic history offshore California. These data are intended for science researchers, students, policy makers, and the general public. Supplemental_Information: 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=L490SC 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. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19900509 Ending_Date: 19900525 Currentness_Reference: ground condition at time data were collected Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -121.090570 East_Bounding_Coordinate: -117.387666 North_Bounding_Coordinate: 31.190785 South_Bounding_Coordinate: 35.321160 Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:dcb63f18-fef7-44af-8e36-da9b6b195c45 Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans Theme_Keyword: geoscientificInformation Theme_Keyword: location Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: substrate Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: marine geophysics Theme_Keyword: sub-bottom profiling Theme_Keyword: geospatial datasets Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords Theme_Keyword: data processing Theme_Keyword: seismic reflection profiling Theme_Keyword: Global Positioning System (GPS) observations 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 Theme_Keyword: shapefile Theme_Keyword: seismic navigation Theme_Keyword: seismic reflection Theme_Keyword: sub-bottom profiling Theme_Keyword: SEG-Y traces Theme_Keyword: R/V Ocean Olympic Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Pacific Ocean Place_Keyword: State of California Place_Keyword: Santa Monica Bay Place_Keyword: San Pedro Bay Place_Keyword: San Pedro Channel Place_Keyword: Gulf of Santa Catalina Place_Keyword: Santa Catalina Island Place_Keyword: Torrance Place_Keyword: Long Beach Place_Keyword: Huntington Beach Place_Keyword: Newport Beach Place_Keyword: Laguna Beach Place_Keyword: Dana Point Place_Keyword: San Clemente Place_Keyword: Oceanside Place_Keyword: Carlsbad Place_Keyword: Encinitas Place_Keyword: Solana Beach Place_Keyword: San Diego Place_Keyword: Coronado Place_Keyword: Imperial Beach Place_Keyword: Avalon Place: Place_Keyword_Thesaurus: NGA GEOnet Names Server (GNS) Place_Keyword: Redondo Canyon Place_Keyword: San Pedro Escarpment Place_Keyword: San Pedro Basin Place_Keyword: Lasuen Knoll Place_Keyword: Carlsbad Canyon Place_Keyword: La Jolla Canyon Place_Keyword: Coronado Canyon Place_Keyword: San Diego Trough Place_Keyword: San Nicolas Basin Place_Keyword: Emery Basin Place_Keyword: San Clemente Basin Place_Keyword: East Cortes Basin Place_Keyword: Cortes Bank Place_Keyword: Tanner Bank Place_Keyword: Tanner Basin Place_Keyword: Santa Cruz Basin Place_Keyword: Arguello Terrace Place_Keyword: Santa Lucia Bank Place: Place_Keyword_Thesaurus: None Place_Keyword: Point Loma 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: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: L490SC.preview.png Browse_Graphic_File_Description: Map of MCS tracklines acquired during USGS field activity L-4-90-SC offshore Southern California. Browse_Graphic_File_Type: PNG Data_Set_Credit: Reprocessing efforts were supported by an Interagency Agreement (IAA) between the Bureau of Ocean Energy Management (BOEM) and the U.S. Geological Survey. The authors acknowledge Danny Brothers (USGS) and Mark Leung (BOEM) for their role in coordinating the IAA. The authors also acknowledge the participants of the field activity L-4-90-SC, the crew of the R/V S.P. Lee and those involved in in survey planning and execution. Native_Data_Set_Environment: SEG-Y reprocessing was conducted in Shearwater’s Reveal seismic software (https://www.shearwatergeo.com/4/reveal-software) version 10.4.2021. Navigation correction used the python package segyio (https://github.com/equinor/segyio). QGIS-LTR (version 3.21, https://www.qgis.org/en/site/) was used to produce the navigation trackline shapefile and preview image. Cross_Reference: Citation_Information: Originator: R.G. Bohannon Originator: S.L. Eittreim Originator: J.R. Childs Publication_Date: 1999 Title: Cruise Report of R/V S.P. Lee, Leg 4, 1990, California continental borderland: U.S. Geological Survey Open-File Report 90-0502 Other_Citation_Details: Bohannon, R.G., Eittreim, S.L., and Childs, J.R., 1990, Cruise Report of R/V S.P. Lee, Leg 4, 1990, California continental borderland: U.S. Geological Survey Open-File Report 90-0502, 10 p., http://pubs.usgs.gov/of/1990/0502/report.pdf. Online_Linkage: http://pubs.usgs.gov/of/1990/0502/report.pdf Cross_Reference: Citation_Information: Originator: Michael A. Fisher Originator: Victoria E. Langenheim Originator: Craig Nicholson Originator: Holly F. Ryan Originator: Ray W. Sliter Publication_Date: 2000 Title: Recent developments in understanding the tectonic evolution of the Southern California offshore area: Implications for earthquake-hazard analysis Other_Citation_Details: Fisher, M.A., Langenheim, V.E., Nicholson, C., Ryan, H.F., and Sliter, R.W., 2009, Recent developments in understanding the tectonic evolution of the Southern California offshore area: Implications for earthquake-hazard analysis, in Lee, H.J., and Normark, W.R., (eds.) Earth Science in the Urban Ocean: The Southern California Continental Borderland: Geological Society of America Special Papers, v. 454, https://doi.org/10.1130/2009.2454(4.2). Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Quality control was conducted during acquisition. Some seismic profiles have gaps in them due to system crashes or intentional shutdowns as required, under terms of our operating permit, to protect marine mammals. Logical_Consistency_Report: Quality control was conducted during acquisition and processing to ensure consistency of SEG-Y header navigation and seismic-reflection data that matches bathymetry along the tracklines. Navigation data are available as a trackline shapefile in the ‘Data Files’ section. Trackline navigation combines SEG-Y line parts into a single-track line (32 tracklines and 32 SEG-Y files, including parts). 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. Seismic data are unavailable where equipment failed and where marine mammal observers determined mammals were within the 250-m shutdown radius. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The primary underway navigational sensor was Loran-C operated in the range-range mode. Loran-C calibration factors were derived from GPS solutions when GPS coverage was adequate(approximately 12 hours per day). The absolute accuracy of LORAN-C varies from 0.10 to 0.25 nmi (185 to 463 m). Repeatable accuracy is much greater, typically from 60 to 300 ft (18 to 91 m) (COMDTPUB P16562.6, "LORAN-C Users Handbook", 1992, https://chetaero.files.wordpress.com/2016/11/loran-c_users_handbook_entire.pdf). Further positional error may have been introduced from assigning receiver locations and CMP binning. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: P.E. Hart Publication_Date: 2016 Title: namss.L-4-90-SC.mcs.airgun.zip Geospatial_Data_Presentation_Form: SEG-Y Publication_Information: Publication_Place: online Publisher: U.S. Geological Survey Online_Linkage: https://walrus.wr.usgs.gov/namss/survey/l-4-90-sc/ Type_of_Source_Media: online database Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19900509 Ending_Date: 19900525 Source_Currentness_Reference: ground condition at time data were collected Source_Citation_Abbreviation: original seismic-reflection data Source_Contribution: seismic shot SEG-Y data for reprocessing Process_Step: Process_Description: Multichannel seismic-reflection data were acquired with a 10-airgun array seismic source with a combined chamber volume of 2424 cubic inches. The data were recorded using a 48-channel analog streamer which were spaced at 50 meter intervals, the furthest offsets was 2.4 kilometers aft of the airgun array. The length of the streamer and the 50 meter shot interval results in a fold of 20 traces or greater. The seismic traces were recorded at 2 ms sample rate with a total record length of 12 seconds. Source_Used_Citation_Abbreviation: original seismic-reflection data Process_Date: 19920520 Process_Step: Process_Description: Raw pre-stack SEG-Y data was imported into Reveal seismic software (https://www.shearwatergeo.com/4/reveal-software, v. 10.4.2019), where The seismic traces were detrended and the applied tape delay was removed. Corrections were applied to the SEG-Y headers which were recorded in reverse channel order and offsets were corrected to positive values. The preceding steps were applied to perform frequency - wavenumber analysis, with which noise and aliased signal were isolated and removed in Fourier space leaving the desired reflection signal. The raw data was quality controlled and 4 noisy channels at the furthest offsets were removed. The data was despiked, cleaned and trim statics were applied. Deconvolution wass done prestack and removed the source signature from the geologic reflections in order to produce crisp, collapsed, and high-resolution imaging. The deconvolution operator is an inverse filter that is computed statistically on a per-channel basis. The detailed 2D subsurface velocity structure was determined in a semblance analysis workflow. The velocity field was used to correctly move out the data before stacking to increase resolution, suppress random noise and reduce contamination from the sea surface multiple. Post-stack time migration was applied at 85 percent of the picked velocity for this data set. Finally, the water column was muted and the bottom edge of the data were muted. Data were exported to SEG-Y format with navigation in standard header byte locations and zipped into L490SC.mcs.segy.zip. CMP navigation was converted from points to a multi-line shapefile in QGIS-LTR (v. 3.21) and zipped into L490SC.mcs.trackline.shapefile.zip. Process_Date: 20200520 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 32 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000001 Longitude_Resolution: 0.000001 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: WGS 1984 Ellipsoid_Name: WGS 84 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257224 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: L490SC.mcs.segy.zip Entity_Type_Definition: Zip archive of seismic shots with time stamp in standard SEG-Y file format Entity_Type_Definition_Source: Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards Detailed_Description: Entity_Type: Entity_Type_Label: L490SC.mcs.trackline.shapefile.zip Entity_Type_Definition: Zip file contains a polyline shapefile (.shp) of the location of each SEG-Y shot point along the navigated tracklines and associated files Entity_Type_Definition_Source: U.S. Geological Survey Attribute: Attribute_Label: LINE Attribute_Definition: Number of navigation line Attribute_Definition_Source: Assigned unique line identifier name Attribute_Domain_Values: Unrepresentable_Domain: Producer-assigned unique line identifier name Overview_Description: Entity_and_Attribute_Overview: Seismic Shots with Time Stamp in standard SEG-Y file format, with trackline navigation presented in polyline shapefile 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 - CMGDS Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Resource_Description: SEG-Y data are available in the zip file L490SC.mcs.segy.zip containing 32 standard SEG-Y format files of seismic shots with time stamp (Society of Exploration Geophysicists (SEG) Technical Standards, available for download at http://seg.org/Publications/SEG-Technical-Standards). A shapefile of the SEG-Y shot-track navigation is available in the zip file L490SC.mcs.trackline.shapefile.zip. 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 (L490SC.mcs.segy.zip) contains the processed seismic data per navigation line. File_Decompression_Technique: The zip file can be decompressed with any zip utility (for example, 7zip, Keka, WinZip). Transfer_Size: 489.1 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.5066/P9FOES4K Access_Instructions: SEG-Y data (L490SC.mcs.segy.zip) can be downloaded using the Network_Resource_Name link and scrolling to the Seismic Data section. Digital_Form: Digital_Transfer_Information: Format_Name: shapefile Format_Version_Number: ArcGIS Pro (version 2.4.1) Format_Information_Content: Zip file contains a shapefile with SEG-Y trackline navigation File_Decompression_Technique: The zip file can be decompressed with any zip utility (for example, 7zip, Keka, WinZip). Transfer_Size: 1.2 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://doi.org/10.5066/P9FOES4K Access_Instructions: Data (L490SC.mcs.trackline.shapefile.zip) can be downloaded using the Network_Resource_Name link and scrolling to the Seismic Data section. Fees: None. Technical_Prerequisites: Use of SEG-Y data requires specialized software, such as Reveal by Shearwater; 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. Users must have software capable of reading shapefile (.shp) format to use the shot point shapefile. Metadata_Reference_Information: Metadata_Date: 20230809 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: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998