Implications of Magma Transfer Between Multiple Reservoirs on Eruption Cycling
Derek Elsworth,1*
Glen Mattioli,2
Joshua Taron,1
Barry Voight,1
Richard Herd3
Volcanic eruptions are episodic despite being supplied by melt
at a nearly constant rate. We used histories of magma efflux
and surface deformation to geodetically image magma transfer
within the deep crustal plumbing of the Soufrière Hills
volcano on Montserrat, West Indies. For three cycles of effusion
followed by discrete pauses, supply of the system from the deep
crust and mantle was continuous. During periods of reinitiated
high surface efflux, magma rose quickly and synchronously from
a deflating mid-crustal reservoir (at about 12 kilometers) augmented
from depth. During repose, the lower reservoir refilled from
the deep supply, with only minor discharge transiting the upper
chamber to surface. These observations are consistent with a
model involving the continuous supply of magma from the deep
crust and mantle into a voluminous and compliant mid-crustal
reservoir, episodically valved below a shallow reservoir (at
about 6 kilometers).
2 Department of Geosciences, University of Arkansas, Fayetteville, AR 72701, USA.
3 School of Environmental Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
* To whom correspondence should be addressed. E-mail: elsworth{at}psu.edu
