Publication Date:
2017-04-04
Description:
In a geothermal area, a detailed knowledge of the three-dimensional velocity structures aids the managementof
the field and the further development of the geothermal source. Here,we present a high-resolution
study of the three-dimensional S-wave velocity structures from microearthquake travel times for the
Larderello-Travale geothermal field, Italy.We have also deduced the Vp/Vs and Vp ×Vs parameters for this
area toemphasize the deep variations in the physical rock properties due to fluid content and porosity. Furthermore,
effective porousmedium modelling has been performed for site-relevant lithologies, to improve
our interpretation of the results in terms of rock physics signatures. This has allowed us to estimate the
variation range of the seismological parameters investigated, as well as their sensitivity for suitable rock
under specific physical conditions. LowVp/Vs anomalies, arising froma lower Vp compared to Vs, dominate
the geothermal field of Larderello-Travale. These have been interpreted as due to steam-bearing formations.
On the contrary, analysis of Vp ×Vs images provides information on the relative changes in rock
porosity at depth. Comparison of tomographic section images with previously interpreted seismic lines
suggests that the reflective ‘K-horizon’ delineates a transition between zones that have different porosities
or crack gatherings. The ‘K-horizon’ also lies on low Vp/Vs anomalies, which suggests a steam saturation
zone, despite the reduced porosity at this depth.
Description:
In press
Description:
1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
Description:
JCR Journal
Description:
open
Keywords:
P- and S-wave velocity
;
Seismic tomography images
;
Geothermal field
;
Rock properties
;
04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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