Nigel there was a 4.9 one 12 hours ago in the Caldera.
The stuff I have been reading says the they reckon there is that much movement now inside the crater over 21 meters subsidence that the ground is that soft that it doesn't create shakes anymore. And its dropping at 08. to 1m per day.
The volcano is inflating, the amount of magma coming out of the eruptions so far is less than they reckon is going into it.
850m worth of ICE on top of the thing is now showing cracks on the top because the bottom has dropped so much.
From what I have read is the ice is acting like a champagne cork and once the magma gets at the ice and melts it the reduction of the weight off the top will let it go pop.
http://www.ruv.is/frett/subsidence-b...eters-possible