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Seismic imaging of a fluid storage in the actively extending Apennine mountain belt, southern Italy
Author(s) -
Amoroso Ortensia,
Ascione Alessandra,
Mazzoli Stefano,
Virieux Jean,
Zollo Aldo
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl060070
Subject(s) - geology , induced seismicity , seismology , fluid pressure , fault (geology) , permeability (electromagnetism) , volume (thermodynamics) , petrology , nucleation , pore water pressure , geotechnical engineering , mechanical engineering , chemistry , physics , organic chemistry , quantum mechanics , membrane , biology , engineering , genetics
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 V P / V S and low V P × V S values, suggesting fluid accumulation within a ~15 km wide rock volume where intense microseismicity is located. The 1980 Irpinia, M s 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 behavior 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.”