Unravelling the Internal Dynamics of Lava Fountains

Overview

Key Features

The eruption of low viscosity magmas (≲ 1,000 Pa s) is the most frequent and volumetrically abundant form of volcanism on Earth and on other planets and satellites. Explosive eruption of these magmas (i.e. episodes or events that produce fragments termed pyroclasts) commonly occurs by lava fountaining and is indicative of magmas spanning a wide range of melt compositions including komatiite, basalt, alkaline mafic melts and carbonatite. Fountains show a great diversity in height and are typically 100’s m but can reach heights of ~1 km. The Unravelling the Internal Dynamics of Lava Fountains programme is offered by University of Liverpool .

During fountaining, hot pyroclasts, originally formed by fluid dynamic induced breakup of the parent magma, are cooled by forced convection and radiative heat loss. Depending on the efficiency of cooling with respect to other timescales (e.g., transport, relaxation), a wide array of deposit textures can be formed. Clasts may be deposited hot, above their glass transition temperature, forming spatter mounds, ramparts and potentially rheomorphic lava flows. In contrast, clasts may be deposited cold, producing tephra cones and laterally extensive tephra blankets. Thus, the deposit type and clast textures formed can ‘forensically’ provide information about the fountain dynamics and the physical properties of the melt.