| Autor: |
Tarantino, Stefania, Poli, Piero, D'Agostino, Nicola, Vassallo, Maurizio, Festa, Gaetano, Ventafridda, Gerardo, Zollo, Aldo |
| Předmět: |
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| Zdroj: |
Nature Communications; 11/14/2024, Vol. 15 Issue 1, p1-10, 10p |
| Abstrakt: |
Pump-probe experiments investigate the strain sensitivity of crustal elastic properties, showing nonlinear variations during the strain cycle. In the laboratory, pre-seismic reductions in seismic velocity indicate that asperity contacts within the fault zone begin to fail before the macroscopic frictional sliding. The recognition of such effects in natural seismic-cycles has been challenging. Here we exploit seasonal hydrological strains, performing a natural analogue to a quasi-static laboratory pump-probe experiment to investigate the nonlinear strain sensitivity of crustal rocks and its role in seismic failure along the tectonically-active Irpinia Fault System (Southern Italy). By comparing 14-years-long series of spring discharge, strain, seismic velocity variations and earthquakes rate, we find that seismicity peaks during maximum hydrological forcing and minimum seismic velocity. Seasonal strains of ~10−6 are required for both earthquake triggering and significant nonlinearity effects arising from modulus reduction. We suggest that, for faults in a critical state, cyclical softening may lead to failure and seasonal seismicity. Through the exploitation of a seasonal hydrological deformation to probe the elastic properties of the crust, the authors here explain variations of seismic waves velocity and triggering of earthquakes in terms of nonlinear elasticity. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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