Quantification of volcano deformation caused by volatile accumulation and release

<p>Magma stored in the crust may exsolve a significant amount of volatiles, primarily CO<sub>2</sub>, but also H<sub>2</sub>O and SO<sub>2</sub> if cooling promotes crystallisation and volatile exsolution. These volatiles may, over time, segregate and accumulate into a gas-rich foam at the roof of the magma body. This is the underpinning process to explain the frequently observed ‘excess gas’ produced in explosive eruptions, where the amount of erupted SO<sub>2</sub> is much larger than can be explained by the mass of erupted products and …