The physics of complex systems: applications to earthquake

摘要: We have seen in the previous two chapters that classical approach to earthquake physics provides an intuitively reasonable model of occurrence. This theory can be successfully applied explain propagation seismic waves radiated by sources. However, is not able account globally for following basic features occurrence (cf. section 1.1), 1 Earthquakes are rare events. 2 Earthquakes clustered both space and time. 3 Earthquakes rupture events which occur mostly on preexisting faults. 4 Earthquakes a quasi-constant stress drop is, average, much smaller than ambient (Abercrombie Leary, 1993). 5 The external forcing function, i.e. tectonic strain, small constant, inducing extremely low strain rates. 6 Fault traces power law distributed length. 7 Faults rough surfaces, with roughness. 8 The spatial distribution hypocentral locations earthquakes laboratory acoustic emissions time (Kagan Knopoff, 1980; Hirata et al., 1987). 9 Earthquakes size (Gutenberg-Richter law). 10 Earthquakes aftershock sequences decay (Omori law). 11 Seismicity induced perturbations individual events. These may due occurring at relatively great distances (see 2.6), or changes local pore fluid pressure through man-made activity.