Oxford researchers discover giant 'balloon of magma' expanding under Santorini

A new survey suggests that the chamber of molten rock beneath Santorini’s volcano expanded 10-20 million cubic metres between January 2011 and April 2012. This has caused the surface of the island to rise by 8-14 centimetres during this period.

The findings were made by a team led by Oxford University scientists, who used satellite radar images and Global Positioning System receivers (GPS) to detect movements of the Earth’s surface on Santorini.

A report of the research, co-authored by St Anne’s Fellow and Tutor in Earth Sciences, Professor David Pyle, appears in this week’s Nature Geoscience. 

In January 2011, a series of small earthquakes began beneath the islands of Santorini – the first sign of activity beneath the volcano to be detected for 25 years. Following the earthquakes, Oxford University researchers spotted signs of movement of the Earth's surface on Santorini in satellite radar images. Undergraduate students then helped researchers complete a new survey of the island. The findings are helping to improve understanding of the inner workings of the volcano, but don’t provide an answer to the biggest question of all: when will the volcano next erupt?

Professor David Pyle, an author of the paper, said:

'For me, the challenge of this project is to understand how the information on how the volcano is behaving right now can be squared with what we thought we knew about the volcano, based on the studies of both recent and ancient eruptions. There are very few volcanoes where we have such detailed information about their past history.'

The team calculate that the amount of molten rock that has arrived beneath Santorini in the past year is the equivalent of about 10-20 years growth of the volcano. But this does not mean that an eruption is about to happen: in fact the rate of earthquake activity has dropped off in the past few months.

The report's findings have received media coverage in the UK and beyond, with comments from David Pyle appearing in the Daily Mail and Science Daily. An interview with David also featured on the BBC World Service Newshour programme on Monday 10 November - listen again here.