Index of /data/reports/1993/93-006/DOC
This is just a description of all the stuff that is contained on the tapes.
Virginia 1990 EDGE experiment
Recorded using the reftek instruments and collected by the University of Wyoming.
Initial processing by Brad Carr at the University of Wyoming
The geophones used in this experiment are Mark Products L-22, 2Hz triaxial and were buried at least 2 feet in the
soil. Some were cemented onto concrete foundations and stn 16 was cemented to a rock.
Each tape represents the recording of a particular line during
the shooting. The refteks that we deployed recorded only line A (line801) and part of line B (line 802). The enclosed
tapes are SEGY format and have a record length of 60s.
Since this experiment was performed on distance increments, the refteks were deployed and then programmed to run continuously
for 2-3 days. Hence to create the 60s records, I used a program called Truecut written by David Okaya to cut the data based on
the time of the shots. The shooting occurred on approximately 20 second intervals, so a 60 second record is a bit of overkill.
Yet, because of the large offsets and attempt to record shear wave arrivals, I decided to make longer records so that further
processing could be done on the traces to obtain information after 20s.
All of the tapes are similar in organization. They have channel defined as either 1, 2, or 3, where 1 is the vertical- 2 is
oriented to magnetic North, 3 is oriented to magnetic East. They have been sorted so the first trace corresponds to the nearest
source offset. This means that the trace 1 is from shot 1484 on line A and shot 935 on line B. Notice that there was
overlap in the shot stations so there are more traces than shots. I have kept those traces and they have a different
sequence number for a given channel. These repeated shots can also be seen in the ffids. In the majority of the data
the ffids are sequential. Where they are not is a repeated section. There were 85 shot points repeated on line A, and
96 shot points on line B.
I have included a tar tape of all of the log and err files that were generated by the ref2segy program. Also,
I placed the diagnostic files that were generated by the truecut program.
Happy Hacking--if anyone has any questions please feel free to contact me at (307) 766-6227.