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Soil gas distribution in the main coseismic surface rupture zone of the 1980, M s = 6.9, Irpinia earthquake (southern Italy)
Author(s) -
Ciotoli Giancarlo,
Bigi Sabina,
Tartarello Chiara,
Sacco Pietro,
Lombardi Salvatore,
Ascione Alessandra,
Mazzoli Stefano
Publication year - 2014
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2013jb010508
Subject(s) - geology , seismology , soil gas , fault (geology) , fault scarp , geomorphology , structural basin , soil water , soil science
Soil gas measurements of different gas species with different geochemical behaviors were performed in the area of the Pecore Plain, a 200 m × 300 m sized, fault‐bounded extensional basin located in the northern Mount Marzano massif, in the axial belt of the southern Apennine chain. The Pecore Plain area was affected by coseismic surface faulting during the M s = 6.9, 1980 Irpinia earthquake, the strongest and most destructive seismic event of the last 30 years in southern Italy. The collected data and their geostatistical analysis provide new insights into the control exerted by active fault segments on deep‐seated gas migration toward the surface. The results define anomalies that are aligned with the NW‐SE trending coseismic rupture of the 1980 earthquake along the western border of the plain, as well as along the southern border of the plain where a hidden, E‐W striking fault is inferred. Geospatial analysis highlights an anisotropic spatial behavior of 222 Rn along the main NW‐SE trend and of CO 2 along the E‐W trend. This feature suggests a correlation between the shape and orientation of the anomalies and the barrier/conduit behavior of fault zones in the area. Furthermore, our results show that gas migration through brittle deformation zones occurs by advective processes, as suggested by the relatively high migration rate needed to obtain anomalies of short‐lived 222 Rn in the soil pores.