Development of Seismic Velocity Analysis Software

[摘要] Seismic velocity analysis software was developed. The main program was written in FORTRAN77 and mounted on a SUN workstation. Options for the users include three types of time correction (reflection, refraction, and continuous velocity increase with depth) and five methods to compute the coherency coefficient value (semblance, energy normalised crosscorrelation sum, statistical normalised crosscorrelation sum, unnormalised crosscorrelation, and the mean amplitude summation). Four S-Macros were written to display the results in the form of contour lines, window peak power, maximum coherency coefficient, and velocity spectrum. The software was tested using synthetic and field data. Two sets of field data were used, the first was recorded for this project using blasts at Newburgh quarry as the source and was called dataset A. The second was data from the South West England Seismic Experiment (SWESE) and was called dataset B. Results obtained, by the software, from dataset A match that of the regression analysis showing two segments of velocities, the first with 5.24 km/s at time intercept of 0.02 s and the second at greater offsets with a velocity of 4.55 km/s at a time intercept of -0.01 s. Some results, of dataset B, obtained by the software confirm a previous interpretation of the data while some other did not. It was concluded that the software could be a useful support tool in guiding or confirming other methods of interpretation, but that the conditions of use had to be carefully evaluated.

[发布机构] University:University of Glasgow

[关键词] Geophysical engineering, Computer engineering