magma

“I suspect the subsurface movement of magma caused severe earthquake activity,” he said.

The size of Strombolian eruptions can vary but are often characterised by intermittent explosions, which occur due to the presence of gas in the magma chamber within the volcano.

“Mt. St. Helens, Mt. Rainier, Mt. Hood, Crater Lake — those kind of volcanoes have a lot more gas and are more explosive in general. The magma is more viscous,” Chadwick said.

“You just have to make sure you don’t get burned by the magma.”

So far, no-one has been able to work out if a volcano becomes more or less explosive when sea water in these vents mixes with magma.