Seismic imaging of a fluid storage in the actively extending Apennine mountain belt, southern Italy

Amoroso, Ortensia and Ascione, Alessandra and Mazzoli, Stefano and Virieux, Jean and Zollo, Aldo (2014) Seismic imaging of a fluid storage in the actively extending Apennine mountain belt, southern Italy. Geophysical Research Letters, 41 (11). pp. 3802-3809. DOI: https://doi.org/10.1002/2014GL060070

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Official URL: http://doi.org/10.1002/2014GL060070

Abstract

A picture of the upper crustal structure of the Irpinia active faults system in southern Italy was obtained by combining new geological evidences, lithological properties, and microseismicity distribution. P and S wave velocity models indicate high VP/VS and low VP × VS values, suggesting fluid accumulation within a ~15 km wide rock volume where intense microseismicity is located. The 1980 Irpinia, Ms 6.9, earthquake nucleated within the same fault-bounded volume. We suggest that concentration of background seismicity is mainly controlled by high pore fluid pressure. Its increase in fluid-filled cracks around major faults leads to earthquakes' nucleation. Seismic pumping along major faults carries fluids through the conduit system represented by the intensely fractured damage zone. Conversely, the cross-fault barrier behaviour of the low-permeability fault core leads to pore fluid pressures building up within the fault-bounded block, thus producing a positive feedback triggering earthquake nucleation within the volume, which behaves as an “earthquake reservoir.”

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Item Type: Article
Subjects: Methodology > Method and procesing > Collective properties of seismicity
Region > Italy
Project: SHEER project