Seismicity and deformation induced by magma accumulation at three basaltic volcanoes

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

We analyzed the evolution of volcano‐tectonic (VT) seismicity and deformation at three basaltic volcanoes (Kilauea, Mauna Loa, Piton de la Fournaise) during phases of magma accumulation. We observed that the VT earthquake activity displays an accelerating evolution at the three studied volcanoes during the time of magma accumulation. At the same times, deformation rates recorded at the summit of Kilauea and Mauna Loa volcanoes were not accelerating but rather tend to decay. To interpret these observations, we propose a physical model describing the evolution of pressure produced by the accumulation of magma into a reservoir. This variation of pressure is then used to force a simple model of damage, where damage episodes are equivalent to earthquakes. This model leads to an exponential increase of the VT activity and to an exponential decay of the deformation rate during accumulation phases. Seismicity and deformation data are well fitted by such an exponential model. The time constant, deduced from the exponential increase of the seismicity, is in agreement with the time constant predicted by the model of magma accumulation. This VT activity can thus be a direct indication of the accumulation of magma at depth, and therefore can be seen as a long‐term precursory phenomenon, at least for the three studied basaltic volcanoes. Unfortunately, it does not allow the prediction of the onset of future eruptions, as no diverging point (i.e., critical time) is present in the model.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Seismicity and deformation induced by magma accumulation at three basaltic volcanoes
Series title Journal of Geophysical Research B: Solid Earth
Subseries Seismology
DOI 10.1029/2008JB005937
Volume 113
Issue B12
Year Published 2008
Language English
Publisher AGU
Contributing office(s) Volcano Hazards Program, Volcano Science Center
Description B12305; 12 p.