A group of Italian researchers working around Mount Etna in Sicily has developed a way of looking inside volcanos which enables experts to better predict eruptions and gauge their violence .
The approach was first tried out on Etna around the time of its eruption in 2002. With computer images based on seismic data, experts were able to chart the build-up of magma and lava in the volcano's interior .
Details of the procedure, which is akin to a doing a series of CAT scans on a hospital patient, have now been revealed for the first time in the new edition of the prestigious monthly Science .
The technique is based on something called seismic tomography, which creates a 3-D image of part of the earth's crust using recordings of the waves produced by earth tremors in the region .
Energy companies have been using this technique for some time to map out petroleum deposits and to locate accumulations of underground gas .
"This is the first time it's been applied to an active volcano and repeated over a period of time", said Domenico Patané, head of the Catania-based research group .
While energy companies only needed to get a single image of any zone in order to see what they want, vulcanologists need several. With multiple images, spaced out over time, they can watch changes take place .
"That way we are able to understand what is happening inside a volcano in periods of eruption and in dormant phases" .
Patené's team made a series of scans of Etna over 18 months, starting in 2001 and ending in early 2003 .
Etna, which is Europe's most active volcano, returned to life in autumn 2002 with a series of tremors that sent lava flowing down the mountainside and ash spewing into the air .
On October 29, a violent quake rocked the volcano's southeastern slopes, damaging buildings and leaving 1,000 people temporarily homeless. The images and information gathered convinced the team that their technique could be applied elsewhere and become a useful tool for predicting the arrival and intensity of volcanic eruptions .
The accuracy of the images, and the information derived from them, depends on the amount of data used to create them. This, in turn, depends on the number of seismic monitoring points positioned around a volcano .
"The technique could be improved by using a larger number of instruments," Patané said, noting however that this would obviously carry a certain cost .
