Identification_Information: Citation: Citation_Information: Originator: David Foster Publication_Date: 2005 Title: L15_27SP100G.SHP - Every 100 shot points from seismic lines 15-27 for USGS cruise GYRE 99002 Edition: 1.0 Geospatial_Data_Presentation_Form: vector digital data Series_Information: Series_Name: Open-File Report Issue_Identification: 2005-1071 Publication_Information: Publication_Place: Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Online_Linkage: http://pubs.usgs.gov/of/2005/1071/data/seismic/1999/chirp/nav/l15_27sp100g.zip Larger_Work_Citation: Citation_Information: Originator: Twichell, D.C. Originator: Cross, V.A. Originator: Paskevich, V.F. Originator: Hutchinson, D.R. Originator: Winters, W.J. Originator: Hart, P.E. Publication_Date: 2005 Title: GIS of selected geophysical and core data in the northern Gulf of Mexico continental slope collected by the U.S. Geological Survey Edition: 1.0 Series_Information: Series_Name: Open-File Report Issue_Identification: 2005-1071 Publication_Information: Publication_Place: Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Other_Citation_Details: 1 DVD-ROM Online_Linkage: http://pubs.usgs.gov/of/2005/1071 Description: Abstract: This GIS overlay is a component of the U.S. Geological Survey, Woods Hole Science Center's, Gulf of Mexico GIS database. The Gulf of Mexico GIS database is intended to organize and display USGS held data and provide on-line (WWW) access to the data and/or metadata. A two week cruise aboard the R/V GYRE focused on mapping surficial sedimentary processes and their connection to the subsurface geology. The study area was on the upper continental slope in the northwestern Gulf of Mexico; an area of active hydrocarbon exploration. Active salt movement, hydrocarbon movement up faults, the presence of gas hydrates associated with biogenic and thermogenic methane, and overpressured sand deposits all present hazards to oil exploration in this area. This study used sidescan sonar and high-resolution chirp subbottom profiling techniques to map the surficial and shallow subsurface expression of these processes in two areas roughly 15 by 25 km in size. High-resolution multi-channel seismic-reflection data were collected simultaneously with the sidescan imagery to provide a link to the deeper subsurface. Additional multi-channel and Huntec seismic data were collected along regional lines between the detailed study areas to tie these studies to other areas of known hydrates and to wells where shallow overpressured sands have been drilled. The detailed studies attempted to map entire geological systems in this upper slope environment to provide a broader perspective than can be seen from studying a single lease block. One study area focused on two adjacent salt withdrawal basins to assess the processes that are shaping the flanks of the basins, the processes affecting sedimentation in the basin floors, and to compare the deeper structures and surficial processes between the basins. The second study area focused on three salt domes, the processes associated with them, and how they affect the shallow subsurface stratigraphy. Initial observations suggest that most of the surface and shallow subsurface geohazards are associated with the flanks of salt structures. Here active salt movement generates faults along which hydrocarbons can escape to the seafloor, and tectonic oversteepenning generates slope failures. Purpose: This GIS data layer shows the shot points along which SIS-1000 chirp subbottom profile data and sidescan sonar data were collected. The first and last shot of each file are included, and the intervening shot points are at a 100-shot interval. The navigation has been corrected to show the SIS-1000 vehicle location rather than the ship location (Foster and others, 2000). Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 19990409 Ending_Date: 19990422 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -91.876353 East_Bounding_Coordinate: -91.572284 North_Bounding_Coordinate: 27.821542 South_Bounding_Coordinate: 27.702872 Keywords: Theme: Theme_Keyword_Thesaurus: General Theme_Keyword: seismic reflection Theme_Keyword: SEG-Y Theme_Keyword: Chirp Theme_Keyword: Datasonics SIS 1000 Theme_Keyword: point shapefile Theme_Keyword: navigation Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Woods Hole Science Center Theme_Keyword: Coastal and Marine Geology Program Theme_Keyword: CMGP Theme_Keyword: Information Archives Field Activity 99002 Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: oceans and estuaries Theme_Keyword: location Theme_Keyword: geoscientificInformation Place: Place_Keyword_Thesaurus: General Place_Keyword: Gulf of Mexico Place_Keyword: Continental Slope Place_Keyword: Louisiana continental slope Access_Constraints: None Use_Constraints: Public domain data from the U.S. government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey (USGS) as the source of this information. Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: David Foster Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2271 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: dfoster@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2005/1071/data/seismic/1999/chirp/nav/l15-27sp100g.gif Browse_Graphic_File_Description: Overview image showing the extent and coverage of the data layer. Browse_Graphic_File_Type: GIF Browse_Graphic: Browse_Graphic_File_Name: http://pubs.usgs.gov/of/2005/1071/data/seismic/1999/chirp/nav/l15-27sp100g-thumb.gif Browse_Graphic_File_Description: Thumbnail image showing the extent and coverage of the data layer. Browse_Graphic_File_Type: GIF Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 2; ESRI ArcCatalog 9.0.0.535 Cross_Reference: Citation_Information: Originator: Foster, D.F. Originator: Twichell, D.C. Originator: Danforth, W.W. Originator: Irwin, B.J. Originator: Nichols, D.R. Originator: O'Brien, T.F. Publication_Date: 2000 Title: Archive of SIS-1000 CHIRP subbottom data collected during USGS cruise GYRE 99002 Gulf of Mexico, 9-22 April, 1999 Edition: 1.0 Series_Information: Series_Name: Open-File Report Issue_Identification: 99-586 Publication_Information: Publication_Place: Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Other_Citation_Details: 3 CD-ROMS Data_Quality_Information: Logical_Consistency_Report: No additional checks for topological consistency were performed on the data. No duplicate features are present. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The ship was navigated with differential GPS, and location of the deep-towed sidescan vehicle was calculated in a variety of ways. In shallow water an acoustic ranging system was used in concert with vehicle depth and ship heading to compute vehicle location. In deeper water depths where the acoustic ranging system did not work, vehicle location was calculated in one of two ways. In some places the amount of wire out was used in place of the acoustic range. In other places, vehicle location was calculated by measuring the offset between features observed on the NOAA multibeam bathymetry and the tow vehicle echo sounder. This offset was measured at several points along each track and was used to compute vehicle navigation. Vehicle location was interpolated between the measured points. Comparison of features on the surface-towed seismic data with the same features on the deep-towed seismic data indicates that the offset mostly is less than 100 m. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Foster, D.S. Originator: Twichell, D.C. Originator: Danforth, W.W. Originator: Irwin, B.J. Originator: Nichols, D.R. Originator: O'Brien, T.F. Publication_Date: 1999 Title: Archive of SIS-1000 CHIRP subbottom data, collected during USGS cruise GYRE 99002 Gulf of Mexico, 9-22 April, 1999 Edition: 1.0 Series_Information: Series_Name: Open-File Report Issue_Identification: 99-586 Publication_Information: Publication_Place: Woods Hole Science Center, Woods Hole, MA Publisher: U.S. Geological Survey, Coastal and Marine Geology Program Type_of_Source_Media: CD-ROM Source_Contribution: Shapefile copies from source publication Process_Step: Process_Description: GPS navigation for the ship and slant-range distances between the ship and the vehicle (when they were available) were logged to disk in the field at a 10 second interval. Source_Used_Citation_Abbreviation: DGPS receiver Source_Produced_Citation_Abbreviation: 99_099.txt-99_111.txt Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: David Foster Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: 508-548-8700 x 2271 Contact_Facsimile_Telephone: 508-457-2310 Contact_Electronic_Mail_Address: dfoster@usgs.gov Process_Step: Process_Description: An acoustic transponder was used to determine range from the ship to the sonar fish; however this system did not always function, particularly in deeper water. Slant range and sonar fish depth below the sea surface were used to calculate the layback distance (horizontal offset) between the ship and sonar fish. The fish was assumed to be directly behind the ship, given the azimuth of the ships track. Different methods were used to calculate or estimate the layback distance for different lines. Lines 15 and 16 of Mosaic Area Two do not have acoustic ranging data available. The SEG-Y file headers contain ship position (UTM zone 15). The ASCII shotpoint navigation files contain geographic coordinates for sonar fish position obtained by comparing fish depth and layback distance from lines 17 and 18 where acoustic slant ranges were good. Because lines 15 and 16 are in relatively shallow water and fish depths did not exceed 300 meters, this method of estimating layback is reasonable. Based on the layback verses fish depth analysis of lines 15 and 16, the horizontal errors may be as much as 50 meters. Layback depends on other variables other than fish depth. Ship speed was not considered in the analysis. Lines 17 and 18 of Mosaic Area Two were determined to have good acoustic slant range, thus the calculated layback was used to obtain sonar fish position. The ASCII shotpoint contain geographic coordinates for sonar fish position as well as ship position. The SEG-Y file headers contain ship position (UTM zone 15). Lines 19-27 of Mosaic Area Two had unreliable slant range information due to the length of fish layback and deeper water. Laybacks were estimated for lines 19 and 20 based on the analysis of fish depth and layback in lines 17 and 18, but when fish depths exceeded 300 meters the error in this method increases. Instead another method of comparing water depth from the sonar fish (fish depth and altitude combined) to NOAA gridded Seabeam bathymetry. Offsets between the bathymetry and the water depth from the fish showed the apparent layback for each line. Using this method, the layback was estimated and the corrected navigation compared to the gridded bathymetry. This showed good correlation between water depths and sea floor features. Furthermore, the estimated layback was used to navigate the sidescan sonar data in the mosaicking process, and features on adjacent sidescan sonar lines matched well. The ASCII navigation files contain ship position as well as layback positions. The SEG-Y file headers contain ship position (UTM zone 15). The processing was done by David Foster, and is summarized in Foster and others (2000) Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: David Foster Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2271 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: dfoster@usgs.gov Process_Step: Process_Description: Shot points were selected from the navigation at a 100-shot interval. The first and last shots of each file were included as well. Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: David Foster Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2271 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: dfoster@usgs.gov Process_Step: Process_Description: The shot point navigation was imported to ArcView and converted to a shapefile. Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: David Foster Contact_Organization: U.S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Contact_Voice_Telephone: (508) 548-8700 x2271 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: dfoster@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Entity point Point_and_Vector_Object_Count: 1837 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.000000 Longitude_Resolution: 0.000000 Geographic_Coordinate_Units: Decimal degrees Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: l15_27sp100g Entity_Type_Definition: Shapefile Attribute Table Entity_Type_Definition_Source: ESRI Attribute: Attribute_Label: FID Attribute_Definition: Internal feature number. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Sequential unique whole numbers that are automatically generated. Attribute: Attribute_Label: Shape Attribute_Definition: Feature geometry. Attribute_Definition_Source: ESRI Attribute_Domain_Values: Unrepresentable_Domain: Coordinates defining the features. Attribute: Attribute_Label: EASTING Attribute_Definition: Shotpoint location - UTM easting Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 610772.44 Range_Domain_Maximum: 640661.13 Attribute_Units_of_Measure: meters Attribute_Measurement_Resolution: .01 Attribute: Attribute_Label: NORTHING Attribute_Definition: Shotpoint location - UTM northing Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 3064957.65 Range_Domain_Maximum: 3077950.39 Attribute_Units_of_Measure: meters Attribute_Measurement_Resolution: .01 Attribute: Attribute_Label: SHOT Attribute_Definition: Shotpoint number Attribute_Definition_Source: USGS Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 6 Range_Domain_Maximum: 11112 Attribute_Units_of_Measure: integer count Attribute_Measurement_Resolution: 1 Attribute: Attribute_Label: LINENUM Attribute_Definition: Line number and file number of the siesmic profile Attribute_Definition_Source: USGS Attribute_Domain_Values: Unrepresentable_Domain: Character string identifying the survey line. Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: David Twichell Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing and physical address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2266 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: dtwichell@usgs.gov Resource_Description: Downloadable Data Distribution_Liability: Although this data set has been used by the U.S. Geological Survey (USGS), no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: SHP Format_Version_Number: 3.3 Format_Specification: ESRI point shapefile Format_Information_Content: The SHP file contains the geospatial data. The SHX file contains the index of the geospatial data. The DBF file contains the attribute data in dBase format. The PRJ file contains the coordinate system information (optional). The AVL file contains the legend information (optional). The SBN and SBX files contain the spatial index of the geospatial data (optional). The XML file contains the metadata describing the data set .shp.xml. An ASCII version of the metadata file. A browse graphic showing the data layer coverage and extent (optional). File_Decompression_Technique: zip Transfer_Size: 0.049 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/of/2005/1071/data/seismic/1999/chirp/nav/l15_27sp100g.zip Access_Instructions: Data may be retrieved via any WWW browser. Offline_Option: Offline_Media: DVD-ROM Recording_Capacity: Recording_Density: 4.75 Recording_Density_Units: Gbytes Recording_Format: UDF Fees: None Technical_Prerequisites: The data are available in Environmental Systems Research Institute (ESRI) shapefile format. The user must have ArcGIS® or ArcView® 3.0 or greater software to read and process the data file. In lieu of ArcView or ArcGIS, the user may utilize another GIS application package capable of importing data. A free data viewer, arcexplorer, capable of displaying the data is available from ESRI at www.esri.com. Metadata_Reference_Information: Metadata_Date: 20051212 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: David Twichell Contact_Organization: U.S. Geological Survey Contact_Position: Oceanographer Contact_Address: Address_Type: mailing address Address: 384 Woods Hole Road City: Woods Hole State_or_Province: MA Postal_Code: 02543-1598 Country: USA Contact_Voice_Telephone: (508) 548-8700 x2266 Contact_Facsimile_Telephone: (508) 457-2310 Contact_Electronic_Mail_Address: dtwichell@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: local time Metadata_Access_Constraints: None Metadata_Use_Constraints: None Metadata_Extensions: Online_Linkage: http://www.esri.com/metadata/esriprof80.html Profile_Name: ESRI Metadata Profile