The ultimate goals of Volcanology are to understand and predict volcanic eruptions. A major challenge for volcanologists is to understand what is happening inside volcanoes even though we can only observe and make measurements at the crater, or outside the volcano. Laboratory experiments can bridge this gap because it is possible to see and measure flow within a laboratory model volcano, at the same time as measuring the externals such as acoustic noise and mechanical vibrations that it emits. In this way, geophysical signals measured at real volcanoes can be interpreted in terms of the processes that are occurring inside that volcano, and hazard monitoring tools can be developed.
The aim of this project is to develop acoustic monitoring as a tool for assessing the state and hazard at a given volcano. Sounds, mostly at frequencies below what we can hear (infrasounds), are produced by all styles of volcanic activity and are thought to be related to gas bubbles and gas flow. Using laboratory experiments, we will characterise the flow patterns that occur in a very viscous liquid, such as magma, through which volcanic gas is passing, and determine the range of gas and liquid fluxes for the different flow patterns. We will also characterise the acoustic signals made by the different flow patterns by measuring the sounds generated in the laboratory experiments, and develop predictive scaling laws for the different flow patterns based on Engineering studies of air-liquid flows in pipes. Finally, we will combine insight from experiment, theory and fieldwork to develop a hazard prediction tool that relates changes in sounds made by a volcano to changes in the gas flux at that volcano.