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| Titel |
Dike emplacement and flank instability at Mount Etna: constraints from a poro-elastic-model of flank collapse |
| VerfasserIn |
Marco Di Bari, Maurizio Battaglia, Valerio Acocella, Marco Neri |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250036950
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| Zusammenfassung |
| We investigated the potential to initiate flank failure on Mount Etna, as a result of
moderate-sized magmatic intrusions. We approximate the dynamic process of a dike intrusion
in a porous media using the framework of a moving volumetric dislocation, assuming a
steady behavior. A vertical planar dike is assumed as most representative of the geometry of
an intrusion at Mount Etna. Given the large uncertainty existing on the range of the physical
and geometrical parameters describing the dynamic process, this steady state representation
can be considered adequate for characterizing pore fluid pressure changes at Etna volcano.
For the geometry used in this study, the analysis of the displacement of a single wedge
(block) is an appropriate mode of failure. Resolution of the forces parallel and normal to the
failure (shear) surface enables the total force FR driving the outward block motion to
be determined. The minimum set of coefficients that describes the stability of the
isothermal system may be determined as FR = FR(a,psc,θ), where θ is the slope
of the groundwater surface, pscis the depth of the detachment surface at the rear
scarp, and a the depth below sea level of the toe of the block. Only two of the three
parameters (a,θ) are somewhat constrained, while psc is practically unknown.
Our analysis shows that when there is no dike intrusion, the block seems to be
practically in stable equilibrium, especially when we consider only the existence of
phreatic aquifers. When we have a dike intrusion, the block is stable in the case
of phreatic aquifers but may be unstable if the block is above a confined aquifer. |
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