Publication Date:
2017-04-04
Description:
The aim of this paper is to discuss a novel approach
to provide insights on the probability of vent opening in calderas,
using a dynamic model of sill intrusion. The evolution of the stress
field is the main factor that controls the vent opening processes in
volcanic calderas. On the basis of previous studies, we think that
the intrusion of sills is one of the most common mechanism governing
caldera unrest. Therefore, we have investigated the spatial
and temporal evolution of the stress field due to the emplacement of
a sill at shallow depth to provide insight on vent opening probability.
We carried out several numerical experiments by using a
physical model, to assess the role of the magma properties (viscosity),
host rock characteristics (Young’s modulus and thickness),
and dynamics of the intrusion process (mass flow rate) in controlling
the stress field. Our experiments highlight that high magma
viscosity produces larger stress values, while low magma viscosity
leads to lower stresses and favors the radial spreading of the sill.
Also high-rock Young’s modulus gives high stress intensity,
whereas low values of Young’s modulus produce a dramatic
reduction of the stress associated with the intrusive process. The
maximum intensity of tensile stress is concentrated at the front of
the sill and propagates radially with it, over time. In our simulations,
we find that maximum values of tensile stress occur in ringshaped
areas with radius ranging between 350 m and 2500 m from
the injection point, depending on the model parameters. The
probability of vent opening is higher in these areas
Description:
This work was supported by the MED-SUV Project
funded by the European Union (FP7 Grant Agreement No. 308665).
Description:
Published
Description:
1703–1720
Description:
2V. Dinamiche di unrest e scenari pre-eruttivi
Description:
JCR Journal
Description:
restricted
Keywords:
Caldera dynamics
;
volcanic unrest
;
sill intrusion
;
vent opening probability
;
volcanic hazard
;
05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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