Why I... believe that volcanoes can be better studied from a safe distance

Jurgen Neuberg
Geophysicist
University of Leeds

Scientists are currently not able to predict the size or nature of a volcanic eruption, although we are close to being able to predict when it will erupt. But in the case of the Goma volcano in the Democratic Republic of Congo, I suspect that no adequate monitoring took place. Many active volcanoes are not monitored because of a lack of funding.

To me, an active volcano is one that has shown some activity over the past 75 years, which means that in Indonesia alone there are about 120. Then there are the underwater volcanoes along the mid-Atlantic ridge. For a long time people have been concerned to monitor volcanoes in inhabited areas, but now they are looking at areas such as Alaska where, although remote, an active volcano could still be a hazard to aviation.

There is widespread misunderstanding about volcanoes. Eruptions are not just one-off events. I have been working in Montserrat where the volcano observatory has made predictions that have led to evacuations before the lava dome in the volcano collapses. There, the volcano has been erupting for the past six or seven years. Since 1995, lava has been coming out continuously at more or less the same rate. Lava piles up in the dome. If the dome is small or sits in stable surroundings, not much happens, but if it grows large enough, it can collapse. In some instances, the dome will get so big that it provokes a landslide: the magma becomes decompressed, causing a huge lateral blast that results in massive ash plumes and pyroclastic flows.

People have been recording the vibrations emitted by volcanoes with seisometers for the past 25 years, but they are looking at a very narrow bandwidth. It is like looking at a picture through a blue-tinted glass. You see only one colour.

My work uses broadband seismic arrays that display the picture in all its colours. More than just saying whether a volcano is active seismically, broadband can indicate what stage of activity a volcano is at and what the pressure changes are. But you also need to measure how much gas is coming out of the dome, the chemical composition of the gas and the tilt and volume of the dome. In Montserrat, the chemistry of the magma means it is very viscous. It piles up in domes and forms a crystalline mass that acts like a cork on a champagne bottle.

The technologies exist to monitor these different parameters - we just need to combine them. Leeds University, along with eight partners, is involved in Multimo, a European-funded project that aims to instal a multiple-parameter observatory on Montserrat. The cluster of geophysical instruments will record more than just seismic data, and these recordings will be directly transmitted to the internet.

We are also modelling the physical conditions inside the volcano, such as the make-up of the magma, so that we can compare their oscillations with the data we have acquired from the observatory to try to understand the signals.

This kind of technology means it is no longer necessary to get so close to the volcano to gather gas samples. Remote instruments still have to be deployed near the volcano, of course, but that does not mean we have to climb into the craters or go near the dome. In Montserrat, we were more than a kilometre away, the helicopter kept its rotor blades running and we were in constant contact with the observatory.

Some experts might argue that you miss things such as the impact of different weather conditions by remote study, but it is a trade-off based on how much risk I am prepared to take and how much I believe that you cannot rely entirely on one type of measurement.