HR: 17:30h
AN: T14A-07    [Abstracts]
TI: Fragmenting magma: experimental investigations of explosive eruptions
AU: * Spieler, O
EM: spieler@lmu.de
AF: Earth and Environment, LMU-University of Munich, Theresienstrasse 41/III, Munich, 80333, Germany
AU: Dingwell, D B
EM: dingwell@lmu.de
AF: Earth and Environment, LMU-University of Munich, Theresienstrasse 41/III, Munich, 80333, Germany
AB: Observation and numerical modeling have long been the dominant means of understanding eruption dynamics of volcanoes. Lab based techniques, developed by the Experimental Volcanology Goup at LMU, were designed to gain insight into the physics of magma fragmentation and explosive eruption dynamics. Various experimental approaches have been aimed at filling the gap between field observations and modeling since the region of interest is beyond direct access. Analysis of the fragmentation threshold led to a systematic investigation of parameters governing the eruption behaviour (e.g., density, permeability, texture; etc.). Further investigations such as measurement of the fragmentation front velocity have yielded insight into the parameters of eruption dynamics, which can be correlated and incorporated into numerical models. As an accompanying measure, the physical characterisation of pyroclastic materials ejected during a single eruption have been the subject of intensive field studies with the first reliable density distributions resulting. By combining the experiments and field observations we have strived to better ascertain the physical constraints on eruption dynamics. Measurements of the permeability of porous magma under turbulent flow regime have also been performed to accompany the fragmentation studies. The experiments reviewed here have significantly influenced the current thinking on explosive eruptions from magma fragmentation to the pyroclastic deposits. Here we will explain why and how.
DE: 8434 Magma migration and fragmentation
DE: 8445 Experimental volcanism
SC: Tectonophysics [T]
MN: 2007 Fall Meeting