Centrifuge modeling of fault propagation through alluvial soils

Abstract

The behavior of alluvial deposits subjected to fault movements in the underlying bedrock is of major concern for critical structures located within fault zones. An understanding of fault propagation through soils would assist in design of such structures, but could also be utilized in geological interpretation of fault displacement history. On the premise that alluvial fault morphology contains shear patterns characteristic of modes and rates of fault displacements, a study was undertaken involving centrifugal and numerical models of reverse faulting. This paper describes the centrifuge model testing performed to backup simultaneous numerical studies (Geognosis Report, 1980), which will be described elsewhere. A comprehensive model test series under earth gravity conditions (1g) involving reverse and normal faulting under different angles has recently been undertaken by Cole (1979). However, model tests performed under 1g-conditions are limited to rather thin soil layers because of their inability to simulate realistic gravity stress conditions. Furthermore, it is not possible to simulate faulting fast enough to include inertial effects with such models.