The scope of earthquake geology

Abstract

AbstractEarthquakes give rise to three principal effects – fault rupture (with subsidiary fracturing), ground shaking from wave propagation, and stress (±fluid-pressure) changes – that influence a wide range of geological processes at varying distances from the source. Many intermittent events are recognizable in the geological record (e.g. an individual turbidite bed in a flysch sequence; renewal of fracture permeability followed by hydrothermal precipitation) and are potentially attributable to seismic events, but positive identification of an earthquake as the cause is often difficult. Earthquake Geology has grown enormously as a discipline since the advent of palaeoseismic techniques for dating prehistoric fault ruptures as an aid to hazard assessment, but has largely focused on surface processes. There is a need to expand our concept of Earthquake Geology to include subsurface as well as surface effects in the full gamut of tectonic settings. The likelihood is that many Earth processes that have hitherto been considered smooth and progressive are, in fact, intermittent and tied to the seismic stress cycle that is integral to deformation in the Earth's crust and lithosphere.