A Repeat Offender

Most people would describe the grounding of planes, the uprooting of families, and loss of life in a fire criminal. But these events can all be caused by a volcanic erruption - a natural event which is famously hard to predict.

This unpredictable nature is partly due to a lack of knowledge; every volcano has its own character and an accurate evaluation of each one is required. The magma ascent path, the nature of the plumbing systems, volatile contents - and the size and activity of the reservoirs themselves - are all important factors in predicting a volcano’s behaviour. The depth and shape of magma reservoirs has a huge influence on the physical-chemical properties of the magma and also on the expulsion of volatiles.

Not much is known about the volcanoes that comprise the islands of the Azores in spite of the large number of studies carried out in the past. Consistent models for the internal structure of volcanoes are still lacking, with important consequences for the volcanic hazard assessment of the area. The number, size and location of magma reservoirs beneath the islands are poorly known.

The THMSG600 stage is enabling scientists to learn more about the worlds volcanoes.

Vittorio Zanon, researcher of the Centro de Vulcanologia e Avaliação de Riscos Geológicos, University of the Azores, is collecting information on the reservoir locations and processes of magmas. To accomplish this he is studying numerous fluid inclusions using microscopy, a Linkam THMSG600 stage, and Raman spectroscopy. These techniques provide information on the composition of gas species co-existing with magma at depth, and on the pressure conditions of fluid entrapment. In this way he can obtain the depths of mineral crystallization, and therefore, the depths of magma reservoirs.

He has now been able to build a 2D model of the magma ascent path through the crust, determine the crust thickness, and the existence of a shallow area suitable for reservoir formation.

All this information aids the geologists in predicting the behaviour of the volcanoes in question. I am not saying that the geologists will be able to prevent an eruption, stall, or indeed divert the flow, - as was so sensationally accomplished in the movie 'Volcano' - but knowing when it is going to re-offend is certainly a start.