Geotechnical Mitigation Strategies for Earthquake Surface Fault Rupture

Abstract

Surface fault rupture can be damaging to structures built on or near active faults if the hazard is not addressed properly. Fault-induced angular distortion and lateral ground strain can cause beams to yield and eventually lead to structural collapse. When avoidance is not possible, geotechnical mitigation strategies can be used. These strategies include spreading fault displacement over a large area, causing the structure to respond with rigid-body movement, and diverting the fault rupture around the structure. The effectiveness of these strategies can vary from protecting life safety to preventing significant damage and can be effective for a range of dip-slip fault displacements. Earth fills should be sufficiently thick and ductile to prevent the underlying fault dislocation from developing at the ground surface. Thick RC mat foundations proved to be especially effective in shielding the superstructure from the damaging effects of the underlying ground movements. Although more challenging to implement because they require excellent fault characterization, several fault diversion strategies have also proved effective at protecting structures from fault movement.