Publication Date:
2023-01-31
Description:
Deep fluids play active roles during the preparatory phases of large earthquakes and, through
their chemical signature, carry information about deep processes within the seismogenic
crust. Due to its inertness and isotopic signature, helium (the lightest noble gas) is a useful
tracer for investigating the processes of storage and transfer of fluids through the crust,
including those prior to hazardous earthquakes. Here we analyse a 12-year earthquake catalogue
from the Irpinia Fault Zone, Italy, to compute the 4He outputs from the seismogenetic
fault zones (from 104 to 106 mol y−1 with an annual tenfold variability) and compare these
with estimates of long-term helium flux. We find that low-magnitude earthquakes (M 〈 4)
efficiently contribute to variations of the crustal helium output into the atmosphere which
supports the impulsive nature of He degassing in tectonically active continental regions. We
conclude that there is a quantitative relationship between crustal helium outputs and the
volume of fault zones, and suggest variations in helium flux may represent a gauge of
changes in the stress field that are related to the nucleation of earthquakes.
Description:
Published
Description:
224
Description:
9T. Geochimica dei fluidi applicata allo studio e al monitoraggio di aree sismiche
Description:
JCR Journal
Keywords:
helium
;
earth degassing
;
earthquakes
;
Near fault observatory
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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