Volatiles are a key component of volcanic activity. The amount of volatiles, depth of magma storage, and ascent rate likely control the variety of eruption styles. Magmatic gases released to the atmosphere during large explosive eruptions can have significant impact on earth’s climate. Monitoring the volcanic gas compositions and fluxes has been successful at anticipating eruptions. Despite its importance on a wide range of aspects of eruptive activity, understanding the role of volatiles and gases is hampered because they escape during magma ascent and thus can’t be directly sampled at depth. Geochemical and petrological studies of magmatic volatiles related to eruption dynamics in the last 30 years have strongly focused on the role of syn-eruptive magma vesiculation, bubble expansion, and magma ascent rate. Here I wish to investigate three aspects of the role of pre-eruptive volatiles in influencing the eruption styles and processes. These are less well known because the traces of such volatiles are difficult to recognize in the erupted deposits. In addition to novel applications of magma storage conditions and crystal zoning analysis, we will also use thermo-physical models of magma ascent to describe gas vesiculation, bubble expansion and the decoupling between exsolved gas and melt phase.
- Earth Observatory of Singapore