A. Tarantola derived the posteriori probability density function for seismic tomography. It says that the probability of a model having a large data error is low, and represents the projection of the data probability density function into the model space. Often such procedures just converge to the prior knowledge. This also means SA is preferentially sampling the model space near the error minima. The bending and diffraction of seismic rays is particularly severe near earthquake faults.
Faults can juxtapose geologic terranes having very different ages and origins.
Having such unusually detailed velocity models, we can properly account for ray bending and construct diffraction tomograms, which are large-scale ultrasound scans. Finding that the Garlock dips below the Mojave suggested the Mojave is much more active than previously thought. This suggestion was reinforced by the 1992 M7.4 Landers earthquake. A survey crosses the Garlock where its trace steps left at a pull-apart basin. Gravity measurements and wildcat oil drilling in the 1950s constrain the low-velocity sedimentary basin.