Logical_Consistency_Report:
Due to modifications to acquisition parameters during the initial days of surveying, the format in which navigation was stored in the SEG-Y headers varies: navigation is stored in either decimal arc seconds (0.01) or decimal arc minutes (0.0001). In order to properly extract and convert navigation to latitude/longitude divisors of 360000 and 600000 were used for decimal arc seconds and decimal arc minutes, respectively. Prior to JD172, the acquisition system did not consistently record longitude as a negative value (western hemisphere). Thus, either 600000 or -600000 was used to convert arc minutes to longitude based on whether the acquisition software recorded negative or positive longitude values. So although each line has a JPEG image, many lines had to be handled differently to acquire consistent results. Inconsistencies exist in the filenaming convention for individual seismic data collection lines. Because the filenames reflect the original data file names acquired in the field, they were left alone.
Completeness_Report:
No data were acquired on the following dates: 6/8/2006, 6/10/2006 6/12/2006, 6/13/2006, 6/15/2006, 6/16/2006, 6/17/2006, 6/18/2006, 6/19/2006, 6/20/2006. These dates correspond to Julian days 159, 161, 163, 164, 166, 167, 168, 169, 170, and 171 respectively. In addition, lines for which no valid seismic data were available were deleted.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
IRIS was navigated with a Real-Time Kinematic (RTK) GPS, with the GPS antenna mounted directly over the seismic transducer. This system can provide positions to within 0.1 meters. However, due to some errors with the acquisition software, this accuracy is reduced. The accuracy is approximately 2 m given the constraints of the acquisition system.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
The transducers for the IRIS system are barely below the water surface - less than half a meter. This depth is not adjusted for during acquisition or processing.
Lineage:
Source_Information:
Source_Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: unpublished material
Title: Data acquisition
Type_of_Source_Media: digital files
Source_Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20060603
Ending_Date: 20060627
Source_Currentness_Reference:
ground condition of data acquisition used to create this dataset
Source_Citation_Abbreviation: none
Source_Contribution:
The data were collected using the USGS WHCMSC Autonomous Surface Vessel (ASV) IRIS. This system is designed to operate in shallow water (1-5 meters). IRIS is a catamaran platform 3 meters in length, 1.2 meters in width, and approximately 118 kilograms. The vehicle is operated remotely through a wireless modem network enabling real-time monitoring of data acquisition. The system is navigated using a ZXW RTK augmented GPS system enclosed on a platform in the middle of the catamaran. An enclosed onboard micro-processor-based motor controller provides signals for speed and steering to hull-mounted brushless direct-current thrusters. A center-mounted keel encloses the chirp dual-frequency (100/400 kHz model 4200 EdgeTech) sidescan-sonar transducers and EdgeTech 424 chirp seismic-reflection hydrophones. Mounted in the port hull are the EdgeTech 424 chirp seismic-reflection transducer and a single-beam 235 kHz echosounder. A Sony IP based wireless video camera is installed on the mast of IRIS for the purpose of obstacle avoidance. An onboard Fluxgate magnetometer provides heading, heave, pitch, and roll. IRIS is powered by 2-4 24-volt NiMH batteries located in each hull and has an approximate run-time of five hours at 4 knots.
Process_Step:
Process_Description:
The seismic data were acquired with an EdgeTech SB-424 sub-bottom profiler and recorded in JSF format using JSTAR, EdgeTech's acquisition software. The research effort within Apalachicola Bay represented the first use of IRIS in full survey mode. As such, the system needed to be 'rung-out' during the first several days of surveying. A file naming convention developed over the first few days of surveying and acquisition settings (hardware and software) were modified several times until standardized settings could be established for Apalachicola Bay. Initial trouble-shooting dealt with several issues including a variation in the field in which navigation was stored within the JSF header and in the resolution of the navigation (seconds of arc vs. minutes of arc). Correcting these issues required re-running particular files though EdgeTech's DISCOVER software and saving new JSF files. Files that were saved through DISCOVER are signified by a 'yes' in the 'discover' field within the shapefile. A 'no' within the 'discover' field, indicates that the JSF file was correct in its original format; re-running through DISCOVER was not required. The JSF files were then converted to SEG-Y format using jsf2segy, a C-program written by Tom O'Brien at the Woods Hole, Science Center, U.S. Geological Survey. See the asv_lines_calibrated polyline shapefile available from
http://pubs.usgs.gov/of/2012/1003/html/catalog.html to determine which files required re-running through EdgeTech's DISCOVER software.
Contact_Information:
Contact_Person_Primary:
Contact_Person: Tom O'Brien
Contact_Organization: U.S. Geological Survey
Contact_Position: Marine Geophysical Systems Expert
Contact_Address:
Address_Type: mailing and physical address
Address: Woods Hole Coastal and Marine Science Center
Address: 384 Woods Hole Rd.
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: (508) 548-8700 x2246
Contact_Facsimile_Telephone: 5084572310
Contact_Electronic_Mail_Address: tobrien@usgs.gov
Process_Step:
Process_Description:
These original SEG-Y files are in IEEE format and were converted to IBM floating point using SIOSEIS. In addition to this conversion, the shot numbers have been renumbered in order to start at one.
Process_Date: 2006
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: Woods Hole Coastal and Marine Science Center
Address: 384 Woods Hole Rd.
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
Process_Step:
Process_Description:
A csh script utilized Seismic Unix (v. 4.0) to generate JPEG images of each seismic profile.
Process_Date: 2006
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: Woods Hole Coastal and Marine Science Center
Address: 384 Woods Hole Rd.
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
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.). 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: 20160629
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
