Previous page     Contents     Next page

3.7 Magma Dynamics and Volcanic Processes

The wide range in chemical composition and physical state of the eruptive products of magmatic systems undergoing volcanic eruptions is ample evidence of the complex interplay of processes at work. Integrated approaches to understanding the inner workings of volcanic systems can only be reliably achieved by the combined effort of field-based studies of volcano monitoring and volcanic products, experimental constraining of the magma parameters and numerical simulations of the possible consequences. The role of the experimental and laboratory-based approach in all of this has grown greatly in recent years due to a number of conceptual and technological advances. Processes such as crystallisation, degassing, bubble nucleation, foaming and fragmentation, occurring over a wide range of timescales, temperatures and pressures, require relatively sophisticated experimental approaches in order to obtain a realistic picture of the physics of eruptions. Nevertheless, the systems of interest must be reduced to a sufficiently small number of parameters such that practical limits of modelling can be achieved and so that the results can be readily applied to problems surrounding eruptive systems.

A new sophistication in the experimental approach to the problem is increasingly noticeable in the past few years. Some of the salient features of the advance of this new experimental volcanology have been achieved at Bayreuth. Two examples of important contributions to this field are the development of experimental techniques for real-time experiments using actual volcanic materials (magma samples) and the achievement of vertically integrated experiments whereby the sequence of processes involved in eruptive processes can be progressively stacked in individual experiments.

The following section demonstrates well the increasing sophistication of an experimental approach to eruptive processes, which is gaining enhanced credibility amongst the wide range of disciplines (e.g., physical field volcanology, geophysical and geochemical monitoring, remote sensing of deformation, active geophysical sounding, microanalytical geochemistry, textural analysis methods) involved in understanding such processes. The examples include combined foaming and fragmentation events in degassing rhyolitic magmas, geospeedometric constraints on the emplacement of volcanic units, and fractographic/textural analysis of volcanic products.

Bayerisches Geoinstitut, Universität Bayreuth, 95440 Bayreuth, Deutschland
Tel: +49-(0) 921 55 3700 / 3766, Fax: +49-(0) 921 55 3769, E-mail: bayerisches.geoinstitut(at)