Frottement et instabilite sismique: lois d'echelle au labo et sur les failles
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Friction and seismic instability: scaling from lab to natural faults
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Though the aim of laboratory experiments on friction is to improve our
understanding of earthquakes, it is not straightforward to compare the
small scale measurements obtained under controlled conditions, to the
seismological and geodetical observations obtained at the natural scale.
In fact, several frictional parameters are difficult to retrieve with
seismological tools. One parameter which can be both measured in the
lab and estimated from real earthquakes - at very different scales -
is fracture energy G. This offers a common ground to investigate
whether the frictional dissipation processes observed in the
laboratory have much in common with those occurring during natural
earthquakes. Surprisingly, both values do scale with slip in a
compatible fashion for a large portion of the magnitude spectrum,
but tend to diverge for earthquakes with slip > 10 cm. Promising interpretations
based on the diffuse nature of damage in real earthquakes may help to
reconcile these differences and explain the similarities.