November 8, 2022
What type of instruments do we need to monitor volcanoes?
Volcanoes are geologic structures that release lava and volcanic gasses onto the surface of the Earth. How volcanoes erupt can be extremely violent. For example, Fuego Volcano in Guatemala erupted in June 2018, destroyed the nearby community of San Miguel Los Lotes, and left many people without a home. Scientists use different instruments to understand and study what’s happening inside a volcano. This type of scientific field is called volcanic monitoring (Figure 1).
Figure 1. A volcanologist uses an instrument called a spectrometer to measure the composition of the gasses being emitted by the Kïlauea volcano in Hawai’i, US Source: https://www.usgs.gov/media/images
There are two types of instruments for volcanic monitoring. The first are devices that must be installed close to the volcano for volcanologists to operate and collect volcanic activity data. For example, some instruments are placed close to volcanic fumaroles (conduits on or close to the volcano from which volcanic gasses escape) to detect the gas’s composition (Figure 2). This technique helps scientists determine if magma is moving toward the surface and whether it must alert nearby towns of a possible eruption.
Figure 2. Two geologists use glass bottles to trap volcanic gasses from a thermal feature to determine its composition later using laboratory instruments. Source: https://www.usgs.gov/media/images
The second group consists of satellite instruments. Satellites are instruments in space that travel around other entities that are greater in size or have a stronger gravitational field. For example, the moon is a natural satellite that travels around the Earth, which is much bigger. The volcanic monitoring satellite instruments that travel around the earth can detect changes in the amount of heat that a volcano emits in the form of lava. They can also measure the type and amount of gasses emitted by a volcano and the direction in which they travel (Figure 3). They can do all of this from space!
Figure 3. An eruption in Soufriere Hills was taken on October 11, 2009, from the United States International Space Station as it passed over the small Island of Montserrat in the Caribbean. This is an example of how satellite imagery can be used to track where volcanic plumes are moving. Source: https://volcano.si.edu/
The second group consists of satellite instruments. Satellites are instruments in space that travel around other entities that are greater in size or have a stronger gravitational field. For example, the moon is a natural satellite that travels around the Earth, which is much bigger. The volcanic monitoring satellite instruments that travel around the earth can detect changes in the amount of heat that a volcano emits in the form of lava. They can also measure the type and amount of gasses emitted by a volcano and the direction in which they travel (Figure 3). They can do all of this from space!
One of the benefits of using satellite instruments to monitor volcanoes is that satellites can constantly obtain information about a volcano. This makes it more convenient to study how volcanic activity changes. Additionally, it is much less dangerous than studying a volcano by being too close to it.
Although satellite instruments provide a lot of benefits for studying volcanoes, they have their limitations. These can suffer damages, and fixing them is very expensive or impossible. That is why it’s also necessary to collect data using instruments installed near a volcano. When monitoring volcanic activity, the more information you have, the better. This is why it’s common to use both instruments to monitor a volcano. This dynamic is somewhat like wanting to describe a plate full of food. Think that your eyes are your satellite instruments, and they will help you describe the food from a distance (“Does the food look good?”, “Will it give me a stomach ache if I eat it?”). At the same time, you have other instruments that require you to come into close contact with the food (your hands and mouth) that will help you describe how the food feels and tastes. In the end, you have a very complete description that goes further than what you can see. Now you can say whether the food tastes good aside from whether it looks good. You get more information!