Publication Date:
2017-04-04
Description:
The 2009-2010 L'Aquila seismic sequence is still slightly occurring along the central
Apenninic Belt (August 2010), spanning more than one year period. The main- shock
(Mw 6.3) occurred on April 6th at 1:32 (UTC). The earthquake was destructive and caused
among 300 casualties. The hypocenter has been located at 42.35°N, 13.38° at a depth of
around 10 km. The main shock was preceded by a long seismic sequence starting several
months before (i.e., March, 30, 2009 with Mw 4.1; April, 5 with Mw 3.9 and Mw 3.5, a
few hours before the main shock). A lot of evidences stress the role of deep fluids porepressure
evolution – possibly CO2 or brines - as occurred in the past, along seismically
activated segments in Apennines. Our geochemical group started to survey the
seismically activated area soon after the main-shock, by sampling around 1000 soil gas
points and around 80 groundwater points (springs and wells, sampled on monthly basis
still ongoing), to help in understanding the activated fault segments geometry and
behaviour, as well as leakage patterns at surface (CO2, CH4, Radon and other geogas as
He, H2, N2, H2S, O2, etc...), in the main sector of the activated seismic sequence, not far
from a deep natural CO2 reservoir underground (termomethamorphic CO2 from
carbonate diagenesis), degassing at surface only over the Cotilia-Canetra area, 20 km
NW from the seismically activated area.
The work highlighted that geochemical measurements on soils are very powerful to
discriminate the activated seismogenic segments at surface, their jointing belt, as well as
co-seismic depocenter of deformation. Mostly where the measured “threshold”
magnitude of earthquakes (around 6), involve that the superficial effects could be absent or masked, our geochemical method demonstrated to be strategic, and we wish to use
these methods in CO2 analogues/CO2 reservoir studies abroad, after done in Weyburn.
The highlighted geochemical -slight but clear- anomalies are, in any case, not dangerous
for the human health and keep away the fear around the CO2-CH4 bursts or explosions
during strong earthquakes, as the L'Aquila one, when these gases are stored
naturally/industrially underground in the vicinity (1-2 km deep). These findings are not
new for these kind of Italian seismically activated faults and are very useful for the CO2-
CH4 geological storage public acceptance: not necessarily (rarely or never) these geogas
escape abruptly from underground along strongly activated faults.
Description:
Government of the Netherlands, EON, Shell
Description:
Unpublished
Description:
RAI, Amsterdam, The Netherlands
Description:
4.5. Studi sul degassamento naturale e sui gas petroliferi
Description:
open
Keywords:
CO2 analougues
;
seismogenic faults
;
04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
Poster session
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