Magma fluxes at an island arc volcano from seismic tomography and thermal modelling: Soufriere Hills Volcano, Montserrat

It is widely believed that andesitic magmas erupted at arc volcanoes are stored in shallow reservoirs prior to eruption, but high-resolution images of focused regions of magma in the shallow crust are rare. By integrating seismic tomography with numerical models of magma chamber growth at Soufriere Hills Volcano in the Carribean, we can reveal the characteristics and dynamics of the magmatic system with a level of detail that no single method has yet achieved. An integrated analysis suggests that a magma chamber of 13 km3 with over 30% melt fraction formed between 5.5 and at least 7.5 km depth. By exploring a range of thermal models involving episodic sill injection, we can estimate the sill radius, emplacement time, and magma flux associated with the growth of the imaged magma chamber.