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| Titel |
Pressure and deformation patterns associated with magma chamber refilling. |
| VerfasserIn |
Paolo Papale, Antonella Longo, Melissa Vassalli, Gilberto Saccorotti, Chiara Paola Montagna, Andrea Cassioli, Salvatore Giudice, Enzo Boschi |
| 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 |
250039636
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| Zusammenfassung |
| Magma chambers, or zones of temporary residence of magma beneath volcanoes, are the site
of intense physical and chemical processes that may deeply modify magma composition and
properties and create the conditions for a new eruption. Several evidences show
that volcanic eruptions are commonly preceded and accompanied by new magma
injection into a pre-existing chamber. Magma injection triggers efficient convection and
mixing between the incoming and resident magmas, and may produce the conditions
for dyke propagation and further magma rise, eventually leading to an eruption.
Although new magma injection in a magma chamber is a potentially hazardous event,
volcano monitoring techniques have not yet progressed to a level where such events
are systematically detected and recognized. Here we present innovative numerical
simulations of magma convection and mixing in chamber+dyke systems that disclose the
complex dynamics associated with buoyant magma injection. The simulations are
performed with GALES, a finite element C++ parallel code that solves the mass,
momentum and energy equations for multiphase, homogeneous, multi-component fluids
in the compressible-to-incompressible flow regimes. Our results reveal pressure
oscillations in the Ultra-Long-Period (ULP) range of minutes, related to the generation of
discrete plumes of rising magma. Very large oscillation wavelengths translate into
comparably ULP ground displacements with amplitudes of order 10-4-10-2 m, as
determined by integrating the Green’s functions in homogeneous infinite medium
from the stress field generated at magma-wall boundaries. Such ULP signals are
increasingly emerging at many volcanoes where broad-band networks are being
deployed. We suggest therefore that new magma injection in magma chambers beneath
volcanoes can be revealed from ULP ground displacement measured at the surface. |
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