Publication Date:
2017-04-04
Description:
The thermofluid dynamics of pyroclastic
flows down the slopes of Vesuvius (Italy) were investigated
using physical modeling of the magma ascent and
pyroclastic dispersal processes. The expected properties
and conditions of the magma, such as its anhydrous composition,
water content, and temperature, were based on
the present knowledge of the magmatic system and were
used as input data for the magma ascent model. The predicted
vent conditions were used to define the boundary
conditions for the simulation of pyroclastic flow dispersal
along selected two-dimensional axisymmetric profiles,
representative of the southern and northern slopes of
Vesuvius. The model employed describes the temporal
evolution of a three-phase mixture composed of a continuous
gas phase and two solid phases representative of
fine and coarse particles. The specific terrain roughness
of the slopes of Vesuvius, caused by the presence of pine
woods and urban settlements, was also estimated and accounted
for by the model. Several simulations were carried
out by assuming different magmatic compositions (in terms of water content and temperature), eruption intensities,
topographic profiles, and flow duration. Pyroclastic
flow dynamics appear to be strongly influenced
by the fountain and atmospheric dynamics showing complex,
unsteady, and, in some cases, non-intuitive behaviors.
The mass flow-rate per unit angle of propagation of
the flow proves to be the most critical parameter controlling
the run-out and, therefore, the hazard on the slopes
of Vesuvius. The two-dimensional topographic profiles
employed also appear to significantly affect the flow
propagation. Simulation outputs allow the quantification
of the spatial and temporal evolution of several flow
variables that are critical in hazard mitigation studies.
The analysis of these variables is extensively described
in a companion paper (Esposti Ongaro et al. 2002, this
volume).
Description:
Published
Description:
155-177
Description:
3V. Dinamiche e scenari eruttivi
Description:
JCR Journal
Description:
restricted
Keywords:
Hazard · Mitigation · Numerical simulation · Pyroclastic flows · Vesuvius
;
04. Solid Earth::04.08. Volcanology::04.08.03. Magmas
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
Permalink
