The eruption of the Eyjafjallajökull volcano in Iceland in 2010 showed us that volcanic eruptions can have major consequences, affecting thousands of people. That is why satellites that keep an eye on volcanoes are extremely important .
Unfortunately most volcanoes around the world are not monitored very well, if at all! A study in Science Magazine showed that out of 440 active volcanoes in the world, 384 have very basic or no monitoring whatsoever. Out of these volcanoes, 65 were identified as being serious risks to large populations.
Earth-observing satellites, such as ESA’s Envisat, can detect disruptions on volcanoes that are unmonitored with the help of Interferometric Synthetic Aperture Radar (InSAR). InSAR is a remote sensing technique that takes two or more radar images over the same area and combines them. We can then see if any surface changes happened between the time when the first and second image were taken. These changes are seen as rainbow-coloured patterns on the new combined image.
As a result of these satellite observations, many volcanoes that we previously thought were dormant are now known to be showing signs of unrest.
The new Sentinel satellites are expected to collect data over all land masses, including volcanoes, every six days for the next 20 years. The first of these satellites will be launched next year, in 2013. This will help in monitoring many of the volcanoes around the world.
With the help of satellites, scientists are trying to understand when volcanic unrest will lead to eruptions. Satellite data can also help countries to draw evacuation plans for people living around volcanoes, whose lives might be in danger.
