Study links subtle, subterranean vibrations to future volcanic activity
Volcanoes would be a lot easier to deal with if they were a bit more predictable. People live in the shadow of volcanoes around the world, often hoping that the richness of the soil created by the magma-spewing structures will outweigh the potential risk of fiery, toxic annihilation. Fortunately, volcanoes like Kīlauea in Hawaii are actually pretty consistent and thus relatively easy to work with. Kīlauea has been erupting since January 3, 1983, and that constant activity has made a great place to test technologies that might help us predict the eruptions of more volatile volcanoes elsewhere.
Two ways to monitor magma
Researchers from the University of Cambridge have been looking at two potential signals that, when taken together, may act as an early warning for eruptions. The first line of data concerned vibrations in the ground around the volcano. There’s often a fair amount of energy pulsing through rock and dirt from a variety of sources, many of which have nothing to do with moving lava. But over the course of four years, patterns could be detected in the speed of the vibrations shifting through the ground. To help make better sense of this low-intensity activity, two sensors were compared, looking for vibrations that started close to one and then moved to the other. This would help filter out seismic activity that originated elsewhere, and thus wasn’t directly tied to Kīlauea.
The second line of data concerned larger changes in the shape of Kīlauea itself. As magma moves through different layers of earth, heat and pressure changes create deformities in the volcano itself, particularly in the main magma chamber below that feeds the volcano. These can sometimes lead to bigger movement, such as when Kīlauea opened up a new ‘waterfall’ of lava into the ocean after a large hunk of mountain fell away.
Putting these data together, researchers are looking at the intersection of all this activity. As the magma chamber fills up, the overall mountain bulges and shrinks. This helps speed up local vibrations in the ground that sensors can detect. Once the magma chamber fill more, pressure underground increases, which we now know further boosts the speed of the seismic vibrations in the ground. This suggests that future detectors will be able to look for these more subtle changes in vibration speeds, rather than waiting for more obvious earthquakes. This should help catch more eruptions before it’s too late for people nearby to react.
Source: 'Bulges' in volcanoes could be used to predict eruptions by University of Cambridge, EurekAlert!