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| Titel |
Insight into vent opening probability in volcanic calderas |
| VerfasserIn |
Flora Giudicepietro, Giovanni Macedonio, Luca D'Auria, Marcello Martini |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127933
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| Publikation (Nr.) |
 EGU/EGU2016-7863.pdf |
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| Zusammenfassung |
| This study provides insight into the possible behavior of volcanic
calderas in pre-eruptive phase and into the most probable location of
the areas prone to vent opening hazard, for cases where sill
emplacement is an important element of the shallow magma transport system.
We consider that the evolution of the stress field is the main factor
that controls the vent opening processes in volcanic calderas and 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. Results show that 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 ring-shaped
areas with radius ranging between 350m and 2500m from
the injection point, depending on the model parameters.
We infer that the probability of vent opening is higher in these areas. |
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