Long-range static directional stress transfer in a cracked, nonlinear elastic crust

Seeing the Earth crust as criss-crossed by faults filled with fluid at close to lithostatic pressures, we develop a model in which its elastic modulii are different in net tension versus compression. In constrast with standard nonlinear effects, this "threshold nonlinearity" is nonperturbative and occurs for infinitesimal perturbations around the lithostatic pressure taken as the reference. For a given earthquake source, such nonlinear elasticity is shown to (i) rotate, widen or narrow the different lobes of stress transfer, (ii) to modify the 1/r2 2D-decay of elastic stress Green functions into the generalized power law 1/r where depends on the azimuth and on the amplitude of the modulii asymmetry. Using reasonable estimates, this implies an enhancement of the range of interaction between earthquakes by a factor up to 5 - 10, that is, stress perturbation of 0.1 bars or more are found up to distances of several tens of the rupture length. This may explain certain long-range...

• Type: Journal
• Year: 2006
• Where: FGCS
• Authors: Guy Ouillon, Didier Sornette
• Keywords: Earthquake Source, FGCS 2006, Lithostatic Pressure, Stress Transfer