Utility of elastic models in predicting fault displacement fields

Abstract

Although elastic models have long been used to model earthquake deformation, their application to fault problems is questionable, as accumulated fault strain is higher and the relevant timescales are longer. We test the utility of using elastic models to predict fault displacement fields by independently measuring the three-dimensional slip (offset) distribution and displacement field of small normal faults. The displacement field is constrained from the topography of the deformed bedding planes; the slip distribution is constrained from stratal offsets in multiple sections of fault-normal saw-cuts. Using the observed slip distribution, we calculate both one- and three-dimensional elastic displacement fields. We find that the large strain associated with fault growth can be accommodated with linear elastic models. Much of the remaining misfit between the data and the model may result from elastic interaction with other nearby faults, the inelastic zone around surrounding fault tips, and prefaulting irregularities in the measured bedding plane surface. Copyright 1998 by the American Geophysical Union.