Cross-validation of Fault Enhancement and Elastic Dislocation Modelling

Abstract

Fault enhancement are extracting discontinuities from the seismic volume. However, those discontinuities are not all genuine faults. Coherent noise, acquisition footprint or processing artefacts can be mistaken for sub-seismic faults. In order to discriminate between genuine faults and artefacts, we are using an independent method: elastic dislocation modelling. Elastic dislocation (ED) modelling assumes that the strain distributions around large-scale faults are primarily controlled by the coseismic slip on them. The stress distribution can be derived from the strain distribution. Finally the sub-seismic fault orientation and density can be estimated from the stress distribution. The fault enhancement and elastic dislocation don't rely on the same underlying assumption and have different limitations. Therefore, if a feature is detected by both methods the confidence that it is a genuine fault is increased. We have applied this approach to a Tunisian case study and successfully identify a remote feature, interpreted as an interference pattern between two major faults.