Any spurious data points were removed during processing. File naming is generally lxfy. Where x is the survey line number and y is the file number along a given survey line. There are a few exceptions that resulted from autofile changing in SonarWiz.MAP +SBP. A few lines are named lxfy_, and a few others are lxfy_00z; where x and y are the same as above and z is the autofile change number.
l8f3 and l26f1.001 had fewer than 50 shot points, so these lines were not included.
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The SB-424 was towed from a starboard-side davit with 2-m of cable out on the R/V Rafael. The navigation for these data were acquired with an Communications Systems International (CSI), Inc. LGBX Pro Differential Global Positioning System (DGPS) receiver and an antenna mounted on the cabin of the R/V Rafael. Unless noted, all DGPS data are referenced to WGS84. The SonarWiz.MAP +SBP acquisition software logged the navigation coordinates (in arcseconds) to individual trace headers, but towfish layback and horizontal distance between the CSI antenna and the towfish was not accounted for. Based on horizontal offsets between the towfish and GPS receiver, and towfish motion behind the vessel, the resulting horizontal accuracy is assumed to be +/- 25 m.
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: unknown
Title: Information unavailable from original metadata.
Type_of_Source_Media: disc
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20100910
Ending_Date: 20100916
Source_Currentness_Reference: Data were not collected on 20100915 due to weather conditions.
Source_Citation_Abbreviation: Information unavailable from original metadata.
Source_Contribution:
Approximately 253 km of high-resolution chirp seismic-reflection profiles were collected using an EdgeTech 3100 portable sub-bottom system and SB-424 towfish (4-24 kHz) on the R/V Rafael of Woods Hole, MA. SonarWiz.MAP +SBP (version 4) acquisition software was used to control the Geo-Star topside unit and digitally log trace data in the Society of Exploration Geophysicists Y (SEG-Y), revision 1, standard format (Norris and Faichney, 2002). The SB-424 towfish was towed astern of the starboard side of the vessel. Navigation coordinates were obtained from a DGPS antenna mounted 3-m above the waterline on the interferometric sonar pole and logged to the SEG-Y trace headers. Data were acquired using a 4.0 to 24.0 kHz frequency sweep, a 10 millisecond pulse length, a 0.1667 second shot rate, a 23 microsecond sample interval, and a 130 millisecond record length. A total of 253 km of seismic data were collected.
Process_Step:
Process_Description:
An executable C-shell script called on SIOSEIS (version 10.2.25) to: 1) read the raw SEG-Y data so that shot number begins at one and increments by one for each SEG-Y file; and, 2) write the shot renumbered data to new SEG-Y files.
Process_Date: 2010
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David S. Foster
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
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:
An executable C-shell script called on Seismic Unix (version 4.1) to read the shot renumbered SEG-Y files, write a Seismic Unix file, and extract SEG-Y trace header information, including shot number, longitude, latitude, year, Julian day, and time of day (UTC) to ASCII text files for each survey line. The data were filtered using AWK (no version) to save records for the first and last shots, and shots at unique longitude/latitude positions in between (2010-003-FA_Chirp424_Uniquesht.csv). Geographic coordinates (WGS84) were converted to UTM zone 19 coordinates (WGS84) using Proj (version 4.6.0), and added to the text files in two new columns. Two lines (l12f1 and l13f1) did not have navigation recorded to the trace header due to generator malfunction on the R/V Rafael. Navigation for these two lines were created by extracting x,y values (CSI LGBX Pro acquired) from HYPACK and merging with shot point values based on time of day.
Process_Date: 2010
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David S. Foster
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
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:
An additional AWK filter was applied to each file containing all shot point records created in the previous step to extract trace header records containing the first shot, last shot, and shots evenly divisible by 500 for each survey line. A 500 shot interval was chosen because it corresponds to the annotation interval provided along the top of the seismic-reflection profile portable network graphic (PNG) images, which are included in the 'GIS_catalog\seisimage\' directory. Lines l12f1,l13f1, l4f1, l5f1,l5f2, l5f2.001,l5f2.002, and l5f2.003 were processed seperately from the rest of the files, and therefore the navigation from these data were concatenated to the other navigation data. End shots had to be extracted individually and appended to the navigation text file.
Process_Date: 201010
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: David S. Foster
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
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:
Text files created in the previous step were concatenated into a comma-delimited text file, then imported into ArcMap (version 9.3) using 'Add XY data' and saved as points in the ESRI shapefile format. The shapefile was then projected from WGS84 UTM Zone 19N to Geographic WGS84.
Process_Date: 2010
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Elizabeth Pendleton
Contact_Organization: U.S. Geological Survey
Contact_Position: Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2259
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: ependleton@usgs.gov
Process_Step:
Process_Description:
Edits to the metadata were made to fix any errors that MP v 2.9.32 flagged. This is necessary to enable the metadata to be successfully harvested for various data catalogs. In some cases, this meant adding text "Information unavailable" or "Information unavailable from original metadata" for those required fields that were left blank. Other minor edits were probably performed (title, publisher, publication place, etc.). Fixed a link to the project page in the abstract. Fixed a link in the cross-reference section to the SEG-Y format documentation. The source information was incomplete and had to be modified to meet the standard. The distribution format name was modified in an attempt to be more consistent with other metadata files of the same data format. The metadata date (but not the metadata creator) was edited to reflect the date of these changes. The metadata available from a harvester may supersede metadata bundled within a download file. Compare the metadata dates to determine which metadata file is most recent.
Process_Date: 20160531
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
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543
Contact_Voice_Telephone: 508-548-8700 x2251
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: vatnipp@usgs.gov
Process_Step:
Process_Description: USGS Thesaurus keywords added to the keyword section.
Process_Date: 20180720
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
Process_Step:
Process_Description: Crossref DOI link was added as the first link in the metadata.
Process_Date: 20191118
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
Process_Step:
Process_Description:
Added keywords section with USGS persistent identifier as theme keyword.
Process_Date: 20200908
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
