Mechanical origin of aftershocks.
Aftershocks are the most striking evidence of earthquake interactions and the physical mechanisms at the origin of their occurrence are still intensively debated. Novel insights stem from recent results on the influence of the faulting style on the aftershock organisation in magnitude and time. Our study shows that the size of the aftershock zone depends on the fault geometry. We find that positive correlations among parameters controlling aftershock occurrence in time, energy and space are a stable feature of seismicity independently of magnitude range and geographic areas. We explain the ensemble of experimental findings by means of a description of the Earth Crust as an heterogeneous elastic medium coupled with a Maxwell viscoelastic asthenosphere. Our results show that heterogeneous stress distribution in an elastic layer combined with a coupling to a viscous flow are sufficient ingredients to describe the physics of aftershock triggering.
Department of Mathematics and Physics and CNISM, Second University of Naples, 81100 Caserta, Italy.
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Lippiello
Department of Mathematics and Physics and CNISM, Second University of Naples, 81100 Caserta, Italy.
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Giacco
Istituto Nazionale Geofisica Vulcanologia, 00143 Roma, Italy.
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Marzocchi
Department of Mathematics and Physics and CNISM, Second University of Naples, 81100 Caserta, Italy.
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Godano
Department of Industrial and Information Engineering and CNISM Second University of Naples, 81031 Aversa (CE), Italy.
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de Arcangelis
D055866:Earthquakes; D055595:Mechanical Phenomena; D008962:Models, Theoretical