Publikationsdatum:
2017-04-04
Beschreibung:
More than 100 3 ~ e / 4i~soeto pe ratios were
measured in CO,-dominated gas samples collected during the
1997-1 998 seismic crisis that shook the Umbria-Marche,
Central Apennines, Italy. Although the gas emissions were
located in a typical "crustal" environment the measured values
delineate variable mixing proportions between mantle-derived
and crustal helium. During the monitoring period anomalous
3 ~ e P r~atieos were observed, together with a significant
increase of fluid outflows. The observed 3 ~ e Pa~noema lies
appear to be driven by stress-induced crustal deformations
affecting micro-fracturing and bulk permeability and, in turn,
by a seismogenic-induced modification of the crustal
permeability of rocks. Since crustal deformations can also
occur aseismically, the geochemical anomalies must be
considered indicators of processes occurring below the surface,
which could eventually help to estimate the probability
increase of an impending earthquake, instead of pure empirical
precursors.
Beschreibung:
Published
Beschreibung:
839-842
Beschreibung:
3.2. Tettonica attiva
Beschreibung:
JCR Journal
Beschreibung:
reserved
Schlagwort(e):
helium
;
earthquakes
;
04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
Repository-Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Materialart:
article
