Modeling earthquakes

Geophysicists began studying earthquakes long before geophysics existed as a recognized field. Two centuries ago Montessus de Ballore identified crustal faulting as the basic phenomenon of earthquake physics. The picture remained essentially qualitative up to the late 1950s, when Eshelby (1957), Keilis-Borok (1959), Maruyama (1963), Burridge and Knopoff (1964) and Haskell (1964) realized that the faulting problem could be treated quantitatively using methods originally developed by applied mathematicians in the late 1800s to solve engineering problems in metals. The ensuing research progressively developed into the new discipline of ‘quantitative seismology’. This discipline views the crust as a deterministic mechanical system with the following features: (1) the lithosphere is subject to stresses of tectonic and gravitational origin; (2) the lithosphere is brittle, and when these stresses exceed some fixed limit the crust ruptures (i.e., an earthquake occurs), thereby emitting elastic waves; (3) the ruptures are similar to plane dislocations.