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GeoTomCG
TOMOGRAPHIC SOFTWARE FOR WINDOWS
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GeoTomCG
TOMOGRAPHIC SOFTWARE FOR WINDOWS
GeoTomCG can process crosshole
or VSP seismic or radar data. Display shows calculated radar velocities.
High velocity zone at depth of 27 m is caused by an abandoned mine.
Other zones of contrasting velocities are geological features. S and
R indicate source and receiver positions, respectively
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| GeoTomCG performs 3D tomographic analyses. Source-to-receiver
traveltimes can be anayzed to calculate velocities, or amplitudes can
be analyzed to calculate attenuation. Source and receiver coordinates
can be in any configuration within a 3D grid. The tomographic analysis
calculates velocity and/or attenuation at points within the grid. Anisotropy
can be specified for each point of the grid. Raypaths can be straight
or curved. The ability to perform 3D analysis is an important advantage
in counteracting the problem of nonuniqueness with crosshole data. Site information can be used to obtain more reliable results and to counteract the problem of nonuniqueness. Options include: 1. Maximum and minimum velocities. 2. Constraints that take into account the uncertainty in site knowledge. 3. Constant velocity in user-selected areas or volumes in the grid. GeoTomCG provides graphical displays of velocities, raypath densities, and other parameters for inspecting results and preparing preliminary reports. These displays can be copied to the Windows clipboard. Plots for quality control include traveltime versus distance, residual versus raypath angle, velocity versus raypath angle, and others. GeoTomCG also provides 3D numerical results and 2D slices of the 3D grid as ASCII files that can be read by commercial 3D and 2D visualization programs for preparing formal reports and presentations. Raypaths can be saved to a file and displayed. Curved-ray amplitude inversions can be performed with curved raypaths from velocity inversions. (Amplitude inversions cannot provide appropriate curved rays because ray bending depends on contrasts in velocity, not attenuation.) The user's manual discusses tomographic analysis of seismic and electromagnetic traveltime and amplitude data. Examples with sample data allows users to practice traveltime and amplitude data processing. GeoTomCG is written in MS Visual C++ and runs under Windows with a graphical user interface. Eight hours of program support can be used for any related task, such as obtaining guidance in using the program most effectively, analyzing a particular data set, or revising the program to make the input or output more compatible with programs the user already has. The Windows time-picking program TomTime provides output in the format used as input for GeoTomCG. |
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