Sample Data Set from GeoLogan97

If you have downloaded the sample data set, it will be located in directory PREFIX/ID-101/1997/15jul/bison, where the PREFIX is your choice of top directory location. The READ.ME file included with the sample Bison data can be used as a reel header, and documents the experiment and local geology determined by a ConeTech survey. To run genvsp, we need to know the experimental geometry as recorded in the observer's log.

OBSERVER'S LOG

• Global Coordinates of Borehole (x,y,z)=(100.0,100.0, 1.025) in meters. BSU defines “Global” coordinates as being whatever coordinate system you are working in, usually set by the project you are tying into. Here, I have made up a value of (x,y) to illustrate how the codes work. The z-coordinate is the top of the casing stub from which down-hole measurements are taken. Normally, the casing elevation would be with respect to sea level. However, in this case, it is relative to the ground surface, since the field day did not include a survey tie in to a bench mark. Note that the z-axis is +UP in global coordinates.
• Local Coordinates of the Source (x,y,z)=(0.0, 1.24, 1.025). The local coordinate system is different, and is taken relative to the bore hole (which is at the origin). Note that the z-axis is + DOWN in local coordinates. The source was oriented with the long axis being East-West, the center of the source was 1.24 meters North of the bore hole.
• Source Polarization of First (and ALL ODD) Files (azimuth,vertical)=(90,135).
• Source Polarization of Second (and ALL EVEN) Files (azimuth,vertical)=(270,135).
• Local Coordinates of the Reference Phone (x,y,z)=(0.0, 2.17, 1.175). The ground was horizontal around the bore hole (which means that the reference phone was buried 0.15m in this case).
• Depth to Top of Water Table. Normally this would be measured in the bore hole. However, in this case, it appears that the PVC casing was sealed at the bottom, and the water level in the bore hole was not an indication of the local water table.
• Geophone Station Spacing. This was 0.25 meters.
• Deepest Geophone Station. This was for the first two shot records (files LOGN0001 and LOGN0002), and the phone was 19.25 meters below the casing elevation.
• Shallow most Geophone Station. This was for the last 2 records (files LOGN0145 and LOGN0146). The phone was at a depth of 1.25 meters below casing elevation.
• Azimuth of bow spring on exiting the bore hole. This was noted at $220^{o}$, but in the dialog on PCA analysis, a guide vector of $240^{o}$ was found to require less manual corrections to the bhod.lst file.