TerraSAR-X satellite: The Santorini volcano expands

Credit: DLR

British researchers have used images acquired by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) TerraSAR-X satellite to create a map showing changes in the Santorini archipelago. 

The cause of the deformation is the Santorini volcano located beneath the archipelago.

In some places, the Kameni Islands inside the flooded caldera have risen by eight to 14 centimetres. 

The breadth of the caldera as a whole has increased by about 14 centimetres since early 2011. 

In the analysis of the radar data, the red and yellow shading shows the areas where the ground has risen the most. The main island of Thira is unaffected by the deformation, thus appearing blue.

Glasses are rattling on the shelves and the ground is rumbling - since January 2011 the earth under the Santorini volcano has been stirring.

Most of the time, it is barely noticeable, but every now and then the inhabitants notice small tremors jolting the volcanic archipelago. Nearly circular, and seemingly carved from stone, the submerged caldera is located in the Aegean Sea.

"It was clear to the local people that something was happening with the volcano - but it wasn't until we saw, among other things, the images from the TerraSAR-X radar satellite that we realised that molten rock was pooling beneath the volcano," says British scientist Juliet Biggs from the University of Bristol.

Images acquired by the German Aerospace Center's (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) satellite show the entire archipelago not just rising, but also expanding.

It has been 3600 years since a powerful explosion formed the large caldera. Since then, a new vent has been gradually forming in the middle of this basin, where today the Kameni islands protrude from the water.

The volcano last erupted in 1950 and then fell dormant again, so the scientists from Oxford and Bristol were all the more surprised when the inhabitants started reporting tremors.

"Tour guides, who often visit the volcano with tourists on a daily basis, told me there was an increase in the quantity of strong smelling gas being released by the summit," explains PhD student Michelle Parks. "The colour of the sea had changed as well."