"Geophysical Special Problem" performed during Ph.D. studies.
Acquisition of Multi-component Seismic Data during research for US Dept. of Energy.
This special project was performed during my studies at Michigan State University.
Project Description: As part of the set of geophysical special problems I investigated
during my degree studies I obtained a 3D multi-component seismic data set
over the Silurian Reef that I was studying for the Department
of Energy. This data was obtained at the same time the second
3D P-wave data set in the field's 4D survey was
acquired. This allowed me to "piggy-back" on the P-wave
survey's energy sources. I recorded the data using the department's
48 channel Geometrics Strataview equipment. Below are some photos
showing the acquisition process and the equipment that was used.
Dr. Van Dam inspects the recording
equipment. This small, portable unit is powered by a car
battery and stores each shot record digitally on an internal
drive. The rest of the equipment includes the geophones
We initially checked out the
recording equipment by laying out the 3-component geophones
in one of the halls in the Natural Science building during
a weekend. Once the system was assembled and powered up
we walked up and down the hall in order to determine which
geophones were recording properly and which of the three
cables related to which channels in the recorder.
Once we had established the
equipment was working properly we used it to perform a 2D
refraction survey in a test area near the campus. This area
was also the site of an on-going hydrology study. Here Dr
Van Dam wires up the sledge hammer (the striker plate is
seen on the ground next to him) that is used as the source
for the survey. The sledge is used to hit the striker plate
in order to send compressional energy into the ground. When
the hammer and the plate meet the wiring completes a circuit
that starts the recorder.
For this "shake-down" the refraction
line had a linear orientation with a regular spacing of
2.5 meters between each of the 3-component geophones.
The large measuring tape that we used to establish this
spacing is seen in the foreground of this photo. The orange
colored recorder can be seen in the background near Dr.
Van Dam. Once the geophones were positioned they were
connect to the cables that ran to the recorder.
This refraction line was shot in order
to field check the equipment prior to its use on my project.
The equipment functioned properly and we obtained a good
For my project we laid out
the geophones in the same configuration that we had during
the shake-down field test near the CO2 injection well. The
well head for the injector can be seen in this photo's background
just off the end of the line. Here I have laid out the geophones
along the measuring tape in approximately the selected spacing
(2.5 meters) in preparation for their final positioning
and connecting to the cables which are seen in the left
foreground. The departments little hand cart seen there
on the right turned out to be an important piece of equipment
as it made moving the equipment around much easier.
Prior to the shooting of the
main survey that we were going to "piggy-back"
on we recorded a refraction survey in order to obtain information
concerning the near surface geology. Here I can be seen
swinging the sledge hammer to hit the sticker plate just
off the end on the line in order to send energy into the
Of course at the end of the
recording all the equipment had to be picked up and stowed
away properly for its return to the university. Here I am
rolling up the trigger wire that connects the hammer / striker
plate to the recorder.
I found this project to be quite
enjoyable. As mainly a seismic interpreter I do not get out
into the field as often as would like and I found that this project was