GEOMETRY AND KINEMATICS OF A CORRUGATED FAULT SURFACE, ARKITSA, GREECE

Fault surface geometry plays a critical role in fault and earthquake mechanics. We have quantified the geometry of the spectacular Arkitsa fault to explore the relationship between corrugations and incremental slip direction. A scan of the fault exposure with 1-m spatial resolution and mm-scale precision reveals corrugations that extend across the entire exposed surface and exhibit nearly self-similar scaling across ~3-20 m wavelengths. Corrugations are made up of 1-5 m wide synforms and antiforms with axes sub-parallel to the slip direction separated by nearly planar regions of similar width. The mean orientation of mm-scale striations is nearly parallel to the mean corrugation axis, yet striation orientation shows a statistically significant correlation with fault surface orientation. We interpret these results as evidence that slip-parallel corrugations perturb near-fault stresses and thus play an important role in fault mechanics.