The geophysical mapping utilized a suite of high-resolution instrumentation to map the surficial sediment distribution, depth and sub-surface geology: dual-frequency 100/500 KHz sidescan-sonar system, 234-KHz interferometric sonar, and 500 Hz -12 KHz chirp sub-bottom profiler. The survey was conducted aboard the M/V Megan Miller August 9-13, 2007. The study area covers 35 square kilometers from about 0.2 km to 5-km offshore of the south shore of Martha's Vineyard, and ranges in depth from ~ 5 to 20 meters.
U.S. Geological Survey, 2009, Comma-Separated Value files of the raw sound velocity profiles collected by the U.S. Geological Survey off the southern shore of Martha's Vineyard, MA, 2007 (CSV Files): Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.This is part of the following larger work.Online Links:
- <https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Bathy/svp/svp_csv.zip>
- <https://pubs.usgs.gov/of/2008/1288/html/gis.html>
Denny, J.F., Danforth, W.W., Foster, D.S., and Sherwood, C.R., 2009, Geophysical Data Collected off the South Shore of Martha's Vineyard, Massachusetts: Open-File Report 2008-1288, U.S. Geological Survey, Woods Hole.Online Links:
The following is a description of file contents:
Line 1: Sequential station number of the sound velocity profile (e.g. cast 1) Line 2: Description of the system used (e.g. SV plus) Line 3: Identification of the columns (Time (M/D/YYYY), Pressure (meters), Temperature (Celsius), Sound Velocity (meters/second), Battery (volts)
The remainder of the text file lists the actual sound velocity profile data. Example:
8/9/2007 16:18,0.46,20.212,1517.62,14.1 8/9/2007 16:18,0.57,20.158,1518.21,14 8/9/2007 16:18,0.49,20.134,1518.49,14
U.S. Geological Survey
(508) 548-8700x2311 (voice)
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jdenny@usgs.gov
Comma delimited text files containing the raw sound velocity profiles collected during USGS Cruise 07011 off the southern shore of Martha's Vineyard, 2007. These data are supplied to provide the raw profile data used to minimize refraction artifacts within the swath bathymetric data.These data are also available within a separate WinZip archive (<https://pubs.usgs.gov/of/2008/1288/GIS_catalog>).
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Pitch, roll, heading, and heave information were recorded using a Coda Octopus F180R motion reference unit (MRU) (see: <http://www.codaoctopus.com/motion/f180/index.asp>) and transmitted via network connection to the SWATHplus data collection software. The MRU sensor was mounted directly above the SWATHplus transducers, thereby minimizing "lever arm" offsets which can lead to positioning and depth errors in the bathymetric data. The F180R series MRU uses two L1 antennas for position and heading accuracy. These were mounted directly above the MRU with an offset of 6.76 meters. The antennas are mounted on a rigid horizontal pole with a separation of 1 meter and are offset from the MRU in a forward/aft configuration. The forward offset of the primary antenna from the MRU is 0.5 meters, with no port/starboard offset.
Sound Velocity Profiles (SVP): Fourteen sound velocity casts were collected at various intervals during the USGS cruise 07011 using an Applied Microsystems SV Plus v2 instrument (see <http://www.appliedmicrosystems.com/products/productDetails.aspx?id=1> for details). Sound velocity profiles (SVP) were generally collected at the eastern and western ends of the survey area, corresponding to the start and/or end of geophysical line data collection. This procedure was primarily followed to coordinate collection of SVP casts with the beginning or end of trackline. This was acceptable because only small variations in the speed of sound were noted throughout the survey area and negligible refraction artifacts were visible within the swath bathymetric data.
At each pre-defined station (i.e. location), the SV plus v2 was slowly lowered to the seafloor using a small shipboard winch. The SV plus v2 was monitored by a member of the science party and as the instrument made contact with the seafloor, the position (i.e. location) was recorded in the lab using HYPACK navigation software. The position was then manually recorded within the cruise log and SWATHplus acquisition software. Upon recovery, the SV plus was connected to an onboard computer via serial port in order to download data using the SV plus v2 communications software, SmartTalk.
Software: SV plus v2, SmartTalk (no version)
Person who carried out this activity:
(508) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@usgs.gov
Software: Microsoft Excel 2004
Person who carried out this activity:
(508) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@usgs.gov
Real-Time Kinematic (RTK) navigation data were collected using an Ashtech Z-Extreme receiver, mounted on the SWATHplus sidemount and recorded using navigation software from HYPACK, Inc (<http://www.hypack.com/new/>). RTK provides accuracies on the order of 10s of centimeters (<http://www.navcen.uscg.gov/>). However, the horizontal and vertical offsets between the hand-winch used to deploy the SV plus v2 sound velocity profiler and the RTK antenna on the SWATHplus sidemount were not accounted for in determining the location of the sound velocity profiler. Thus, the horizontal accuracy of the sound velocity locations is considered to be +/- 10 meters.
All sound velocity profiles collected during USGS Cruise 07011 are included within the WinZip archive (<https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Bathy/svp/svp_csv.zip>).
All sound velocity profiles were acquired with the same instrument during the course of USGS Cruise 07011; an Applied Microsystems SV plus v2.
Are there legal restrictions on access or use of the data?
- 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 as the originator of the dataset.
(508) 548-8700x2311 (voice)
5084572310 (FAX)
jdenny@usgs.gov
Downloadable Data
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. 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.
Data format: | WinZip file containing ASCII text files and associated metadata of the sound velocity profiles collected during USGS Cruise 07011 in format WinZip (version 9.0) Size: 40 KB |
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Network links: |
<https://pubs.usgs.gov/of/2008/1288/GIS_catalog/Bathy/svp/svp_csv.zip> |
These data can be viewed with any software package able to read comma delimited text files.
508-548-8700 x2311 (voice)
508-457-2310 (FAX)
jdenny@usgs.gov