Scientists think they can now explain the sequence of events deep inside the Earth that led to the major volcanic eruptions on Iceland earlier this year.
Using data from satellite radar, GPS, and seismometers, the group has sketched a blueprint for the "plumping" underneath Eyjafjallajokull.
The analysis is published in the journal Nature.
It goes someway to explaining why the volcano caused so much disruption to European air traffic.
"We can say that each volcano has a plumbing system and with our observations we have come up with a model for the plumbing system that was active at Eyjafjallajokull during this whole event," said Professor Freysteinn Sigmundsson from the University of Iceland.
"We were surprised by how complex it was," he told BBC News.
The root cause of the eruptions was a major intrusion of magma below the mountain.
This was picked up in the middle of 2009 as a very subtle change in the shape of the volcano, detected at a GPS station.
It prompted Sigmundsson and colleagues to deploy a full array of instrumentation to track the mountain's behaviour.
BBC News
