Soil gas degassing during the 2009 L’Aquila earthquake: study of the seismotectonic and
fluid geochemistry relation.
N. Voltattorni, F. Quattrocchi, A. Gasparini, A. Sciarra
Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata 605, 00143 Rome (Italy)
Corresponding author: nunzia.voltattorni@ingv.it
Abstract
A Mw 6.3 earthquake occurred on April 6, 2009 in the Abruzzo region (Central Italy),close to
the city of L’Aquila. The aftershock area extended for a length of more than 35 km and included
major aftershocks and thousands of minor events. The earthquake ruptured North-West (NW)–
South-East (SE) oriented normal fault dipping toward the South-West (SW), with the city of
L’Aquila lying a few kilometers away on the hanging wall.
A soil gas survey (CO2 and CH4 flux measurements, soil gas measurements and collection) has
been carried out in an area of 24 km2 (few kilometers far from L’Aquila city) both to investigate
the gas-bearing properties of local seismogenic faults (Paganica, Bazzano, and MonticchioFossa faults) and to locate fracture systems when masked by unconsolidated lithologies.
Anomalous values of Rn and CO2 were detected both east of Bazzano fault and in the central
part of the investigated area where faults have no surface expression. Highest He and CH4
values prevail in the southern sector in correspondence with Onna village located between Fossa
and San Gregorio faults. Results of this research provide some clues on the spatial influence of
active tectonic on gas migration toward the surface.
Keywords: soil gas prospecting, gas anomalies, L’Aquila earthquake
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