TY  - JOUR
PY  - 2002//
TI  - Transient dynamics of vulcanian explosions and column collapse
JO  - Nature
A1  - Clarke, A. B.
A1  - Voight, B.
A1  - Neri, A.
A1  - Macedonio, G.
SP  - 897
EP  - 901
VL  - 415
IS  - 6874
N2  - Several analytical and numerical eruption models have provided insight into volcanic eruption behaviour, but most address plinian-type eruptions where vent conditions are quasi-steady. Only a few studies have explored the physics of short-duration vulcanian explosions with unsteady vent conditions and blast events. Here we present a technique that links unsteady vent flux of vulcanian explosions to the resulting dispersal of volcanic ejecta, using a numerical, axisymmetric model with multiple particle sizes. We use observational data from well documented explosions in 1997 at the Soufrière Hills volcano in Montserrat, West Indies, to constrain pre-eruptive subsurface initial conditions and to compare with our simulation results. The resulting simulations duplicate many features of the observed explosions, showing transitional behaviour where mass is divided between a buoyant plume and hazardous radial pyroclastic currents fed by a collapsing fountain. We find that leakage of volcanic gas from the conduit through surrounding rocks over a short period (of the order of 10 hours) or retarded exsolution can dictate the style of explosion. Our simulations also reveal the internal plume dynamics and particle-size segregation mechanisms that may occur in such eruptions.<p /> <p>Language: en</p>
LA  - en
SN  - 0028-0836
UR  - http://dx.doi.org/10.1038/415897a
ID  - ref1
ER  -