Bulletin of Volcanology

, Volume 74, Issue 4, pp 873–880

Magma convection and mixing dynamics as a source of Ultra-Long-Period oscillations

  • Antonella Longo
  • Paolo Papale
  • Melissa Vassalli
  • Gilberto Saccorotti
  • Chiara P. Montagna
  • Andrea Cassioli
  • Salvatore Giudice
  • Enzo Boschi
Research Article

DOI: 10.1007/s00445-011-0570-0

Cite this article as:
Longo, A., Papale, P., Vassalli, M. et al. Bull Volcanol (2012) 74: 873. doi:10.1007/s00445-011-0570-0

Abstract

Many volcanic eruptions are shortly preceded by injection of new magma 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 into shallow magma chambers can lead to hazardous event, such injection 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 multiparametric 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 into magma chambers beneath volcanoes can be revealed by ULP ground displacement measured at the surface.

Keywords

Magma dynamicsMagma convectionMagma mixingULP ground displacement

Supplementary material

445_2011_570_MOESM1_ESM.avi (5.3 mb)
Supplementary Movie 1This movie shows magma composition for the Mount Etna case. Initial compositions are made of 90 wt.% of the corresponding component and 10 wt.% of the other component, to avoid numerical shifts to component fractions >1 or <0. The zero on the depth scale corresponds to sea level (AVI 5,412 kb)
445_2011_570_MOESM2_ESM.avi (5.5 mb)
Supplementary Movie 2This movie shows overpressure for the Mount Etna case. Overpressure is given by pressure at local time–space minus the pressure at same place and time zero. The zero on the depth scale corresponds to sea level (AVI 5,645 kb)
445_2011_570_MOESM3_ESM.avi (5.3 mb)
Supplementary Movie 3This movie shows gas volume fraction for the Mount Etna case. Calculated gas volume and multiphase magma densities at magma interface and time zero are 10 vol.% and 2,250 kg/m3 (shallow magma), and 35 vol.% and 1,700 kg/m3 (deep magma). The zero on the depth scale corresponds to sea level (AVI 5,433 kb)
445_2011_570_MOESM4_ESM.avi (5 mb)
Supplementary Movie 4This movie shows composition for the Campi Flegrei case. Initial compositions are made of 90 wt.% of the corresponding component and 10 wt.% of the other component, to avoid numerical shifts to component fractions >1 or <0. The depth scale on the left refers to meters below sea level (AVI 5,157 kb)
445_2011_570_MOESM5_ESM.avi (2.3 mb)
Supplementary Movie 5This movie shows overpressure for the Campi Flegrei case. Overpressure is given by pressure at local time–space minus the pressure at same place and time zero. The depth scale on the left refers to meters below sea level (AVI 2,308 kb)
445_2011_570_MOESM6_ESM.avi (2.2 mb)
Supplementary Movie 6This movie shows gas volume fraction for the Campi Flegrei case. Calculated gas volume fractions and multiphase magma densities at magma interface and time zero are 3.5 vol.% and 2,400 kg/m3 (shoshonite), and 7.5 vol.% and 2,350 kg/m3 (basalt). The depth scale on the left indicates meters below sea level (AVI 2,284 kb)
445_2011_570_MOESM7_ESM.doc (13.5 mb)
ESM 1(DOC 13,835 kb)

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Antonella Longo
    • 1
  • Paolo Papale
    • 1
  • Melissa Vassalli
    • 2
  • Gilberto Saccorotti
    • 1
  • Chiara P. Montagna
    • 1
  • Andrea Cassioli
    • 3
  • Salvatore Giudice
    • 1
  • Enzo Boschi
    • 4
  1. 1.Istituto Nazionale di Geofisica e VulcanologiaSezione di PisaPisaItaly
  2. 2.School of Geological SciencesUniversity College DublinBelfieldIreland
  3. 3.Dipartimento di Sistemi e InformaticaUniversità di FirenzeFlorenceItaly
  4. 4.Istituto Nazionale di Geofisica e VulcanologiaRomeItaly