Metadata: Identification_Information: Citation: Citation_Information: Originator: Gina M. Brewer Originator: Robert A. Morton Originator: Dana S. Wiese Publication_Date: 2001 Title: Archive of Boomer Seismic Reflection Data Collected on USGS Cruise 99SCE01, Little River Inlet to the entrance of Winyah Bay, South Carolina, 8 June - 16 June, 1999. Geospatial_Data_Presentation_Form: Seismic Reflection Profile Section Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: 01-326 Publication_Information: Publication_Place: St. Petersburg, FL Publisher: U.S. Geological Survey Online_Linkage: http://pubs.usgs.gov/of/2001/of01-326/ Description: Abstract: This report consists of two-dimensional marine seismic reflection profile data from South Carolina. These data were acquired in June of 1999 with the Research Vessel G.K. Gilbert. The data are available in a variety of formats, including binary, ASCII, HTML, and GIF images. Binary data are in Society of Exploration Geologists (SEG) SEG-Y format and may be downloaded for further processing or display. Reference maps and GIF images of the profiles may be viewed with your Web browser. For more information on the seismic surveys see http://walrus.wr.usgs.gov/infobank/g/g199sr/html/g-1-99-sr.meta.html These data are also available via GeoMapApp (http://www.geomapapp.org/) and Virtual Ocean ( http://www.virtualocean.org/) earth science exploration and visualization applications. Purpose: Marine seismic reflection data are used to image and map sedimentary and structural features of the seafloor and subsurface. These data are useful in mapping the extent and thickness of shallow sedimentary units in the near shore region of South Carolina and in assessing other submarine geologic characteristics and features. The main objective of this cruise was to determine the characterization of the geological framework in the near shore region, between Little River Inlet to the entrance of Winyah Bay, for ongoing erosion studies. Supplemental_Information: Seismic reflection profiles are acquired by means of an acoustic source (usually generated electronically), and a hydrophone or hydrophone array. Both elements are typically towed in the water behind a survey vessel. The sound source emits a short acoustic pulse, which propagates through the water and sediment columns. The acoustic energy is reflected at density boundaries (such as the seafloor or sediment layers beneath the seafloor), and detected at the hydrophone. This process is repeated at intervals ranging between 100 ms and 1s depending on the source type. In this way a two-dimensional image of the geologic structure beneath the ship track is constructed. Seismic data are stored in SEG-Y format, which is a standard digital format that can be read and manipulated by most seismic-processing software packages. The SEG-Y file format includes a 3200-byte descriptive header that contains detailed information regarding the data acquisition and processing parameters. All data presented here are stored in SEG-Y, Integer, Motorola format. The SEG-Y formatted trace data files have a .tra extension. Additional recording parameters for each seismic data file can also be found in the .par file associated with each .tra file. However, the .par files and the trim_gga.pln file are only needed to replay the data with Triton Elics Delph Seismic software. WARNING: The acquisition system used to collect the seismic data presented in this report, may have added 6 ms to the top of each seismic trace. However, since no bathymetric data was simultaneously collected with the seismic data we have no way of proving that the added 6 ms does exist for this data set. The seismic source employed here was a "boomer" transducer towed on a sled at the sea surface providing 100 joules per shot. The reflected energy was received by an Innovative Transducer Inc. (ITI) solid core streamer and recorded by PC-based Triton-Elics Delph Seismic acquisition software. The ITI streamer contains 10 hydrophones evenly spaced over 6 meters however only data received by elements 5-8 where summed, resulting in a higher signal to noise ratio for the data. The streamer was positioned parallel to the boomer sled and laterally separated from it by 7 m. The sled was towed 20 m behind the GPS antennae. The sample frequency of the data was 16000 Hz and the total record length was 100 ms. The fire rate was every 0.25 sec, which resulted in a shot spacing of about 0.5 m based on survey speeds of 3.5-4 knots. Differential GPS navigation was fed to the acquisition system every second by the R/V G.K. Gilbert's onboard navigation system, a Trimble Nav Graphic receiver. The accuracy of this receiver is within 100 m, however, the data proved to be of poor quality and required extensive editing. A filter was designed to remove spurious data values and these edited results can be used to generate trackline maps at any scale or projection desired, however the data has not been corrected to reflect the 20 m offset between the source and the GPS antenna. Also the raw navigation files did not have year or Julian day written to the headers. This information was handwritten into the edited and shotpoint navigation files. Position fixes for every 500th shotpoint are also provided as an aide for easy registering of the data after projection. The trackline maps provided in this report are geographic projections (no datum) and were created using ESRI's GIS software ArcView 3.2 and exported to Adobe Illustrator for further editing, then saved as GIF images. These GIF images are viewable with your WWW browser. All navigation files are stored as flat ASCII text files. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19990608 Ending_Date: 19990616 Currentness_Reference: Data assumed to be constant over time but may change due to geologic processes. Status: Progress: Complete Maintenance_and_Update_Frequency: None Planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -79.18 W East_Bounding_Coordinate: -78.55 W North_Bounding_Coordinate: 33.84 N South_Bounding_Coordinate: 33.19 N Keywords: Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:cc8739de-7f17-436c-98d5-df67d4ce4581 Theme: Theme_Keyword_Thesaurus: none Theme_Keyword: marine seismic reflection Theme_Keyword: boomer Theme_Keyword: 99SCE01 Theme_Keyword: ISO 9660 CD-ROM Theme_Keyword: SEG-Y Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: distributions Theme_Keyword: substrate Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) Keywords Theme_Keyword: seismic reflection Theme_Keyword: marine geophysics Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: seismic reflection methods Theme_Keyword: sub-bottom profiling Theme_Keyword: marine geophysics Place: Place_Keyword_Thesaurus: none Place_Keyword: South Carolina/Georgia Coastal Erosion Study: Phase II Place_Keyword: Charleston Harbor Place_Keyword: Murrell's Inlet Place_Keyword: Winyah Bay Place_Keyword: Myrtle Beach Place_Keyword: Little River Inlet Access_Constraints: None. These data are held in the public domain. Use_Constraints: The U.S. Geological Survey request to be acknowledged as the originator of the data in future products or derivative research. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Robert A. Morton Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing address Address: 600 Fourth Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 803-8747 X3080 Contact_Electronic_Mail_Address: rmorton@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2001/of01-326/MAPS/SCMAP.GIF Browse_Graphic_File_Description: Map of trackline data collected on USGS cruise 99SCE01, in June of 1999, in the near shore region of South Carolina between Little River Inlet and the entrance to Winyah Bay. This map is a geographic projection (no datum) with the NOAA chart 11535 in the background as a geotif. It was created in ESRI's GIS software ArcView 3.2, then exported to Adobe Illustrator for further editing and saved as a GIF image. Browse_Graphic_File_Type: GIF Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2001/of01-326/MAPS/groupa.gif Browse_Graphic_File_Description: This is a map of trackline data, containing only group A tracklines. This map is a geographic projection (no datum) with the NOAA chart 11535 in the background as a geotif. It was created in ArcView 3.2, and then exported to Illustrator and saved as a GIF image. This map also contains every 500th shotpoint position information for tracklines in group A. Browse_Graphic_File_Type: GIF Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2001/of01-326/MAPS/groupb.gif Browse_Graphic_File_Description: This is a map of trackline data, containing only group B tracklines. This map is a geographic projection (no datum) with the NOAA chart 11535 in the background as a geotif. It was created in ArcView 3.2, and then exported to Illustrator and saved as a GIF image. This map also contains every 500th shotpoint position information for tracklines in group B. Browse_Graphic_File_Type: GIF Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2001/of01-326/MAPS/groupc.gif Browse_Graphic_File_Description: This is a map of trackline data, containing only group C tracklines. This map is a geographic projection (no datum) with the NOAA chart 11535 in the background as a geotif. It was created in ArcView 3.2, and then exported to Illustrator and saved as a GIF image. This map also contains every 500th shotpoint position information for tracklines in group C. Browse_Graphic_File_Type: GIF Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2001/of01-326/MAPS/groupd.gif Browse_Graphic_File_Description: This is a map of trackline data, containing only group D tracklines. This map is a geographic projection (no datum) with the NOAA chart 11535 in the background as a geotif. It was created in ArcView 3.2, and then exported to Illustrator and saved as a GIF image. This map also contains every 500th shotpoint position information for tracklines in group D. Browse_Graphic_File_Type: GIF Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2001/of01-326/MAPS/groupe.gif Browse_Graphic_File_Description: This is a map of trackline data, containing only group E tracklines. This map is a geographic projection (no datum) with the NOAA chart 11535 in the background as a geotif. It was created in ArcView 3.2, and then exported to Illustrator and saved as a GIF image. This map also contains every 500 shotpoint position information for tracklines in group E. Browse_Graphic_File_Type: GIF Data_Set_Credit: We thank Rich Young with the USGS and Dave Bennett with Eckerd College, captains of the R/V G.K. Gilbert, for their help in the data collection; BJ Reynolds with the USGS, in St.Petersburg, Fla. for his contribution to the data collection process; Dave Foster and Jenna Hill, of the USGS Seafloor Mapping Group in Woods Hole, Mass. for providing examples of their archives; Jon Childs with the USGS, in Menlo Park, Calif. who provided examples of his formal metadata; Brock Murch and Bryan McCloskey at the USGS, in St.Petersburg, Fla. for their programming efforts in editing the navigation files; Shawn Dadisman at the USGS, in St.Petersburg, Fla. for her help with the content and layout; Trent Faust and Rob Wertz with the USGS in St. Petersburg for their help in the web design and technical layout of the CD-ROM; and Laura Moore and Jack Kindinger also both with the USGS in St.Petersburg, Fla. for their technical and editorial reviews. Native_Data_Set_Environment: SEG-Y Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: The validity or accuracy of marine seismic reflection profiles is highly qualitative, and depends on equipment and operating condition variables. Visual inspection of the images rendered from the data did not show any major anomalies. WARNING: The acquisition system used to collect the seismic data presented in this report, may have added 6 ms to the top of each seismic trace. However, since no bathymetric data was simultaneously collected with the seismic data we have no way of proving that the added 6 ms does exist for this data set. Logical_Consistency_Report: This data set is from a single cruise with consistent instrument calibrations. Completeness_Report: These data are collected along tracklines (2D). Therefore, data are inherently incomplete. Geologic details between lines must be inferred. All tracklines were recorded to 100ms. There was no data collected for lines 7,8 or 9. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The position accuracy was determined with the onboard navigation system, a Trimble Nav Graphic receiver in differential mode. Absolute position accuracy was within 100 m. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: The vertical position was local sea level and there has been no corrections to a datum or for tidal variations. Lineage: Process_Step: Process_Description: Boomer processing: Raw SEG-Y data was processed with SU and (Triton Elics Software)to produce the GIF formatted seismic profiles included in this report. A representative data processing sequence consisted of: 1)Bandpass filter: 300-500-2500-3000 Hz; 2)Automatic gain control; 3)Postscript display at 25ms/in and 300shots/in for all tracklines. 4)Convert Postscripts to GIF format Process_Date: 2001 Process_Step: Process_Description: Positional (navigation) data: As the seismic reflection data were acquired, the position of the vessel was continuously determined with the Differential Global Positioning System (DGPS). Positions were recorded approximately every second, and written to the SEG-Y header. The ASCII navigation files were extracted from the SEG-Y headers using SU scripts. Process_Date: 2001 Process_Step: Process_Description: Editing navigation: The ASCII navigation files were extracted from the SEG-Y headers, and then run through a filter to edit out the spurious fixes. The filtered data was also reformatted for use with ESRI's GIS software ArcView 3.2. The edited navigation files also had year and Julian day handwritten to each file. Process_Date: 2001 Process_Step: Process_Description: Open File preparation: No processing has been done to the SEG-Y data files provided on this CD-ROM. The data were displayed as 8-bit gray scale Postscript files using the Seismic Unix 'psimage' algorithm. The Postscript images were then converted to GIF images with Aladdin Ghostscript. Only the GIF images are presented here. Process_Date: 2001 Process_Step: Process_Description: Keywords section of metadata optimized for discovery in USGS Coastal and Marine Geology Data Catalog. Process_Date: 20170124 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Alan O. Allwardt Contact_Position: Contractor -- Information Specialist Contact_Address: Address_Type: mailing and physical address Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-460-7551 Contact_Facsimile_Telephone: 831-427-4748 Contact_Electronic_Mail_Address: aallwardt@usgs.gov Process_Step: Process_Description: Added keywords section with USGS persistent identifier as theme keyword. Process_Date: 20201013 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: VeeAnn A. Cross Contact_Position: Marine Geologist Contact_Address: Address_Type: Mailing and Physical Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: 508-548-8700 x2251 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: vatnipp@usgs.gov Spatial_Data_Organization_Information: Indirect_Spatial_Reference: Horizontal X and Y locations (latitude and longitude) for each shot location are provided in ASCII position files, along with the time the shot was recorded in Greenwich Mean Time (GMT). Direct_Spatial_Reference_Method: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000278 Longitude_Resolution: 0.000278 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: WGS 84 Ellipsoid_Name: WGS 1984 Semi-major_Axis: 6378137 m Denominator_of_Flattening_Ratio: 298.257 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: Binary data file: Each profile is available as a binary file in Society of Exploration Geophysicists SEG-Y format. A SEG-Y file consists of 1) a 3200-byte file identification record of ASCII formatted general information; 2) a 400-byte binary record with information such as sample rate and record length specific to the data set; and 3) multiple records, one seismic reflection trace per record. Each trace record is preceded by a 240-byte "trace header" containing information such as trace number and acquisition day and time specific to each trace. The trace data are represented as a time series of unit less 16-bit integer or 32-bit real numbers proportional to the reflection coefficient. The SEG-Y file is useful only if you have access to specialized software designed to process and display seismic reflection data. These SEG-Y files have a .tra extension. These .tra files range in size from the smallest being 14 MB to the largest being 142 MB. Entity_and_Attribute_Overview: Graphic image file: Each profile is available as a GIF image. The trackline maps provided are GIF images that contain hot-links to the seismic profile GIF images. The profiles range in size from 560KB to 5.8MB. Entity_and_Attribute_Detail_Citation: Barry, K.M., Cavers, D.A., and Kneale, C.W., 1975, Recommended standards for digital tape formats: Geophysics, v. 40, n. 2, p. 344 - 352. Also available online at: Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Rob Wertz Contact_Organization: U.S. Geological Survey Contact_Position: Manager - Data Management Group Contact_Address: Address_Type: Mailing address Address: 600 Fourth Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 803-8747 X3045 Contact_Electronic_Mail_Address: rwertz@usgs.gov Contact_Instructions: Data may be available on-line only by special arrangement with the distributor above. Resource_Description: U.S. Geological Survey Open-File Report 01-XXX CD-ROM Distribution_Liability: This Compact Disc-Read Only Memory (CD-ROM) publication was prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data published on this CD-ROM have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and/or the functioning of the software. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data, software, or related materials. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: SEG-Y Format_Information_Content: The SEG-Y standard format (Barry and others, 1975) consists of the following: a 3600-byte reel identification header with the first 3200 bytes consisting of an ASCII header block and a 400-byte binary header block. Both headers include information specific to line and reel number. The trace data block follows the reel identification header. The first 240 bytes of each trace block is the binary trace identification header. The seismic data samples follow the trace identification header. File_Decompression_Technique: none Transfer_Size: 650 Digital_Transfer_Option: Offline_Option: Offline_Media: CD-ROM Recording_Format: ISO 9660 Compatibility_Information: Unix, Linux, DOS, MAC Digital_Form: Digital_Transfer_Information: Format_Name: SEGY data download Format_Information_Content: The SEG-Y standard format (Barry and others, 1975) consists of the following: a 3600-byte reel identification header with the first 3200 bytes consisting of an ASCII header block and a 400-byte binary header block. Both headers include information specific to line and reel number. The trace data block follows the reel identification header. The first 240 bytes of each trace block is the binary trace identification header. The seismic data samples follow the trace identification header. File_Decompression_Technique: none Transfer_Size: 650 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://cmgds.marine.usgs.gov/data/99sce01/boomer/ Fees: available from the Denver Open-File Sales department, prices vary. Technical_Prerequisites: Use of SEG-Y data requires specialized seismic processing software, such as Unix or Linux based public domain software Seismic Unix (SU) developed by the Colorado School of Mines, Center for Wave Phenomena, which can be downloaded from free of charge. Metadata_Reference_Information: Metadata_Date: 20201013 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Gina M. Brewer Contact_Organization: U.S. Geological Survey Contact_Position: Geologist - Data Management Group Contact_Address: Address_Type: Mailing address Address: 600 Fourth Street South City: St. Petersburg State_or_Province: FL Postal_Code: 33701 Country: USA Contact_Voice_Telephone: (727) 803-8747 X3120 Contact_Electronic_Mail_Address: gmbrewer@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998