Satellites can spot underground supplies of volcanic magma from space
The best way to find volcanic activity brewing under the ground may be to look from space. While magma and gas aren’t directly visible until a volcano actually erupts, their accumulation underground can cause the ground surrounding a volcano to deform. These deformations aren’t necessarily big enough to be noticed by the naked eye, they can be detected by special GPS sensors staked in the ground surrounding the volcano. However, these sensitive instruments can’t be everywhere at once, which is why researchers from Penn State are looking into looking for these subtle shifts in the ground from over 1000 miles above the Earth’s surface.
While a lot of information can be gleaned from visual photography, the imaging in this study was actually a form of radar. Known as Interferometric Synthetic-Aperture Radar (InSAR), this technology creates topographic maps precise enough to show changes in elevation as small as a one-third of an inch. This allowed them to track a three-inch bulge in the ground north of the Masaya volcano in Nicaragua which was attributed to a growing pool of magma that was otherwise undetected. It’s not that the traditional GPS monitors weren’t sensitive to these shifts, but that they just didn’t have the range of satellite imaging, and thus couldn’t pick up on changes in the ground two miles away from the volcano’s open crater.
Better predictions from bigger pictures
This wider range of detection then offers a number of benefits. By monitoring a larger swath of territory, we increase the odds that we’ll detect deformations in terrain that could predict eruptions before people are in danger. The Masaya volcano is known to have blasted ash and lava in a radius of 30 miles during a 1772 eruption, which is probably the kind of thing the two million people that now live within 12 miles of the volcano would like to be ready for.
Beyond human safety, getting more data about volcanic activity will help researchers better understand how volcanoes work in the first place. A build-up of magma two miles from the actual volcano shows that there’s a lot more to these systems than the cone we see on the surface. If more of that system can be tracked and measured with a satellite, it will help build more accurate models about how magma and pressure leads to eruptions in the first place. That will then make future observations, possibly from space, all the more useful in predicting eruptions in other locations around the world.
Source: Wider coverage of satellite data better detects magma supply to volcanoes by David Kubarek, Penn State News
