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| Titel |
Magma convection and mixing dynamics as a source of Ultra-Long-Period oscillations |
| VerfasserIn |
A. Longo, P. Papale, G. Saccorotti, C. P. Montagna, A. Cassioli |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250062374
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| Zusammenfassung |
| Many volcanic eruptions are shortly preceded by new magma injection into a pre-existing,
shallow (< 10 km) magma chamber, causing convection and mixing between the incoming
and resident magmas. These processes may trigger dyke propagation and further magma rise,
inducing long-term (days to months) volcano deformation, seismic swarms, gravity
anomalies, and changes in the composition of volcanic plumes and fumaroles, eventually
culminating in an eruption. Although new magma injection in shallow magma chambers is a
potentially hazardous event, its occurrence is still not systematically detected and recognized.
Here we present the results of numerical simulations of magma convection and mixing in
geometrically complex magmatic systems, and describe the multi-parametric dynamics
associated with buoyant magma injection. Our results reveal unexpected pressure trends and
pressure oscillations in the Ultra-Long-Period (ULP) range of minutes, related to
the generation of discrete plumes of rising magma. Very long pressure oscillation
wavelengths translate into comparably ULP ground displacements with amplitudes of
order 10-4 – 10-2 m. Thus, new magma injection in magma chambers beneath
volcanoes can be revealed from ULP ground displacement measured at the surface. |
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