The Intersection Model for Intraplate Earthquakes

Abstract

Abstract The tectonic cause of intraplate earthquakes has remained enigmatic. As newer data became available, several common features were apparent for intraplate earthquakes occurring in a wide variety of geologic terranes. These have been incorporated in the intersection model. Seismicity occurs near the intersection of, and by the reactivation of, preexisting zones of weakness. The intersections are the foci of anomalous stress build up in response to the ambient stress field due to plate tectonic forces. This anomalous stress buildup is relieved by strike slip motion on a suitably oriented fault and, due to kinematic adjustment, is followed by vertical or horizontal movement on the intersecting fault. The intersection model has several elements that complement other models proposed to explain intraplate earthquakes.