Publication Date:
2019-10-10
Description:
An edited version of this paper was published by AGU. Copyright (2010) American Geophysical Union.
Description:
Monitoring of quiescent volcanoes, such as Campi Flegrei (Italy), involves the
measurement of geochemical and geophysical parameters that are expected to change as
eruptive conditions approach. Some of these changes are associated with the hydrothermal
activity that is driven by the release of heat and magmatic fluids. This work focuses on
the properties of the porous medium and on their effects on the signals generated by the
circulating fluids. The TOUGH2 porous media flow model is applied to simulate a shallow
hydrothermal system fed by a source of magmatic fluids. The simulated activity of the
source, with periods of increased fluid discharge, generates changes in gas composition,
gravity, and ground deformation. The same boundary conditions and source activity were
applied to simulate the evolution of homogeneous and heterogeneous systems,
characterized by different rock properties. Phase distribution, fluid composition, and the
related signals depend on the nature and properties of the rock sequence through which the
fluids propagate. Results show that the distribution of porosity and permeability affects all
the observable parameters, controlling the timing and the amplitude of their changes
through space and time. Preferential pathways for fluid ascent favor a faster evolution,
with larger changes near permeable channels. Slower changes over wider areas
characterize less permeable systems. These results imply that monitoring signals do not
simply reflect the evolution of the magmatic system: intervening rocks leave a marked
signature that should be taken into account when monitoring data are used to infer
system conditions at depth.
Description:
This work was carried out within the research project V1-UNREST, founded by the Italian Civil Protection Department
Description:
Published
Description:
B09213
Description:
3.6. Fisica del vulcanismo
Description:
JCR Journal
Description:
open
Keywords:
hydrothermal circulation
;
observable
;
volcanic unrest
;
permeability
;
03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
;
04. Solid Earth::04.08. Volcanology::04.08.01. Gases
;
04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
