Monitoring the La Soufrière de Guadeloupe hydrothermal system with a regularly-spaced muon telescope network
Abstract
Long-term muon tomography allows to track density changes in a volcano by
continuously measuring the flux of cosmic muons traversing the geological body. In the
context of volcanic hydrothermal systems, this approach can help to determine zones of
preferred steam formation, condensation, water infiltration and storage. A single muon
telescope provides an integrated 2-D average-density section of a volcanic system,
leading to an intrinsically ambiguous inverse problem. To overcome this limitation, we
present the first results of imaging the La Soufrière de Guadeloupe dome and shallow
hydrothermal system with several simultaneous muon telescopes viewing the dome
from different positions around its base. Our strategy provides better constraints on the
spatial location of the density changes and an improved estimate of the amount of mass
involved in these changes. Therefore, we can better characterize water phase changes
and estimate pore pressures. We compare the temporal density variations extracted
from different muon telescopes to time-series of rainfall on the summit recharge area
and temperature profiles in the vicinity of ground thermal anomalies and summit
fumaroles.