Name/Title
S21.05.020Description
The COCORP truck caravan moving west to east across Coshocton County, Ohio. The Vibroseis trucks served as the source of the ground vibrations. Multiple trucks were used to increase the energy injected into the ground. Shown here is the interior of the recording truck used elsewhere to record the signals after they returned to the surface. The recording truck was also known at the “doghouse.” This is where the signals from the geophone sensors on the ground are collected and transferred to magnetic tape. It also contains equipment that signals the vibrator trucks to begin operation. Normally the doghouse is stationary while the vibrators move down the road. The doghouse has a sophisticated switching equipment that allows it to select which sensors on the ground are being recorded at any given time. It also provides a display of the signals in real time so that the operators can monitoring for any problems with the recording equipment. The photograph was taken by Michael C. Hansen in October 1987. The location is approximate to an area in southern Coshocton County where the seismic line was produced.
In the autumn of 1987, the Consortium for Continental Reflection Profiling (COCORP), based at Cornell University in Ithaca, New York, conducted a National Science Foundation funded seismic-reflection profile across Ohio. Five 22-ton vibrator trucks owned by Seismograph Services of Tulsa, Oklahoma, sent vibrations to depths of 25 miles or more into the ground. The reflected seismic data profile is used as the primary data source for investigation of the deep crustal structure beneath the United States. The two seismic lines in Ohio were the result of a proposal that the Ohio Division of Geological Survey submitted to COCORP to investigate a north-south oriented zone in western Ohio that appears to be a major area of discontinuity in Precambrian basement rock. Seismic reflection profiling, as carried out by COCORP, uses truck-generated vibrations as a source of energy to probe deep into the earth's crust. These vibrations bounce off boundaries, known as reflectors, representing changes in rock types or major structural features and return to the surface, where they are picked up by sensitive recording devices called geophones. The data are recorded and stored on computer tapes and then processed to produce a vertical cross section of the area traversed. The cross section displays the reflectors encountered by the seismic waves.
This slide image included in the USGS National Digital Catalog for NGGDPP Grant G15AP00115 in FY2015.
REVIEW
Date Estimate Source: Story in Columbus Dispatch places the truck caravan in Delaware and Knox Counties during the first week of October, see: "Shaken Bedrock May Offer Clues to Ohio's Depths" by David Lore (Dispatch Science Reporter), Home Final Edition, Section News 3D, 11 October 1987.
Location Estimate Source: "Structure Contour Map on the Precambrian Unconformity Surface in Ohio and Related Basement Features" by Mark T. Baranoski (Ohio Geological Survey, Columbus 2013) Digital Map Series PG-23.
For more information, see: COCORP Traverse Across Ohio by Michael C. Hansen (Ohio Geological Survey, Ohio Geology Newsletter, Fall 1987) page 1+. AND "How the World Was Made"--The COCORP Traverse of Ohio by Michael C. Hansen (Ohio Geological Survey, Ohio Geology Newsletter, Winter 1989) page 1+.
From Dr. Larry D. Brown of Cornell University's Institute for the Study of the Continents in an e-mail to Lisa Long on July 13, 2016: Lisa's Question: S21.05.021 shows equipment on one of the trucks. What is this equipment called? What is its part in the process? Dr. Brown's Answer: This picture, and the following one, appear to be from within the recording vehicle, which is also known at the “doghouse”. This is where the signals from the sensors on the ground (e.g. Geophones} are collected and transferred to magnetic tape. It also contains equipment that signals the vibrator trucks to begin operation. Normally the doghouse is stationary while the vibrators move down the road. The doghouse hasContext
Equipment radios inside of room, fire extinguisher below. Vibrator truck caravan in Coshocton County, Ohio.