Abstract
In the last decades, volcano monitoring capabilities have increased
enormously, thanks to geochemical and geophysical airborne and surface
measurements that have steadily improved their accuracy and time
resolution. Such a wealth of data is routinely used to track volcanic
unrest and eruption evolution, although precise causative links with
underground processes are often missing. Modeling of magmatic and
volcanic systems has also leaped forward, thanks to the increased
availability of computer power and development of numerical models.
Capturing the complexity of magmatic system evolution at all scales is
nonetheless still a challenge: the crystal- and bubble-size processes
need to be taken into account in order to resolve the reservoir-scale
dynamics detected by the monitoring networks. We have developed a robust
numerical model to solve the thermo-fluid dynamics of magmatic mixtures,
that includes pressure-, temperature and melt composition-dependent,
locally (space-time) defined properties and constitutive equations of
multi-component magmas. The model has been applied to a variety of
scenarios related to magma dynamics in underground volcanic systems,
including magma arrival from depth into shallow reservoirs. Model
results include the space-time evolution of density, pressure, velocity
and composition within the domain, that can be used as sources of
synthetic geodetic and seismic datasets, akin to those recorded by
monitoring networks. The synthetic and monitoring time series can thus
be compared and their similarities can be exploited to detect the
underground dynamics causing well-defined time and spectral patterns: we
are building a physically sound reference for the interpretation of
volcanic unrest signals and their relationships with the deep magma
dynamics. This approach has been successfully used to detect shallow
magma arrival from strainmeter records at Campi Flegrei during the
ongoing unrest phase; it is also being applied to evaluate how precise
gravity surveys at Mount Etna can help in detecting any shift in the
eruptive sequence.