Back projection imaging techniques to infer the complex earthquake rupture process

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Contents: Problem framing Introduction Problem framing
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The earthquake rupture process

An earthquake is a transient process occurring when the stress accumulated by the tectonic loading is abruptly released on one or several fractures of the earth crust. Much of the stored elastic strain energy of the source region is consumed in heating and fracturing of the rocks, but a portion is converted into seismic waves that propagate outward from the fault zone.
The rupture originates at the hypocenter (or nucleation point) and expands over the fault plane as a rupture front, whose shape and velocity depend on the properties of the rock and on the stress extent. Each element of the fault plane radiates energy in the form of P and S waves (body waves) only when reached by the rupture front. Seismic waves carry on the information about the source process and their recording at the Earth surface is used to infer the rupture properties in terms of its space-time evolution.
ifundefinedshowcaptionsetup Sketch of the rupture propagation on the fault plane starting from the hypocenter. When invested by the rupture front, the points of the fault dislocate and radiate energy in the form of seismic waves.