Although a growing number of volcanic eruption models is being developed
using a variety of conceptual approaches, it is imperative that all models use
the same values for these fundamental parameters so that their individual
performance can be assessed. By running models in this way, the differences in
results will reflect contrasting formulations, and thus provide insights into
the processes being modeled. A specific set of experiments will be devised by
the modelers at the workshop using a common protocol (but with individual
approaches and formulations). The objectives of the workshop will thus be to
produce a standard set of parameters and a set of model "experiments" to be
performed by the all models.
Consequently, the workshop will bring the growing community of
volcanic eruption modelers together with experimentalists and observationalists
to accomplish two specific objectives:
1. Ensure that modelers are provided the most up-to-date values of magmatic
parameters on the basis of recent experimental results and observations, and
2. Establish a standardized set of model "experiments" with identical magma and
conduit characteristics and with a common protocol so that model results can be
subsequently meaningfully compared and evaluated.
The workshop will be aimed to set up a suite of "experiments" and assess model
performance using the growing body of experimental data and observations as
constraints. With this result, modeling participants will return to their labs,
and in the following months, will perform the full suite of model runs,
providing the specific set of output required by the standard protocol. The
results will be subsequently compiled and evaluated to determine the sources of
differences in model output. (Based on prior experience with model
intercomparison workshops, there are sure to be major differences.) Modelers
will then be able to revisit their models to explore the sensitivity of their
formulations to variations in functionalization so that the key differences can
be pinpointed. It is expected that once this is done, it will point to specific
magma characteristics that are insufficiently understood. This, in turn, will
spur experimentalists to return to their labs to focus attention on the most
critical parameters identified by the model intercomparison results.
At the workshop, the participating experimentalists and monitoring specialists
would "bring to the table" a set of constraints to be used by all models in
their parameterization. In recent years, new experimental results have provided
tighter constraints on magmatic parameters including:
• chemical diffusivity,
• thermal diffusivity,
• volatile solubility, and
• pre-eruptive dissolved volatile concentration.
In order to construct the most accurate model possible, it is necessary to use
as realistic values for the above parameters as possible. In addition, recent
experimental results have provided insights into the processes of
• bubble nucleation and growth,
• two phase conduit flow
• foam rheology, and
• fragmentation dynamics.
The presently unrealized opportunity now exists to incorporate these emerging
results into numerical models as well.
The workshop will identify the specific model "experiments" to be run
by the various participating modeling groups, and will provide the specific
parametric constraints so that model results can be meaningfully assessed. This
will then set the stage for a second meeting, where the results of the model
runs can be compared and the differences explored and reconciled.