Integrated high-resolution tomography

Marco A. Perez, John C. Bancroft

A common problem in seismic tomography is the inadequate amount of data required for accurate traveltime inversion. The inherent nature in which data is acquired and the subsurface velocities of the survey area can result in a nonuniform distribution of raypaths. In such instances the statistical nature of tomographic inversion biases the solution to reflect the acquisition instead of the geologic properties. This work outlines a method for using the quasi-null space, a measure of inversion reliability, to produce a more constrained solution. In this method, two seismic experiments with different acquisition geometries are used to determine velocity models over the same geologic region. Using the well-constrained portions of the two resulting velocity models, as determined from the quasi-null space, a final tomogram is determined. Testing shows that the combination of two seismic experiments over the same geologic model and null space analysis yield superior tomograms.