A volcanic eruption occurs when magma from the earth’s mantle manages to penetrate the crust , reach the surface and leave in the form of gases, ash and lava . As we can see in this previous article, there are different reasons why a volcano can arise: from the collision or separation of tectonic layers, to landslides and earthquakes, among others.
However, knowing the reasons for the eruptions does not make them easier to predict. While geologists can measure the thickness and weight of the earth’s crust, the study is complicated by trying to collect data related to magma. The high temperatures and depths of the magmatic chambers make it very difficult to quantify the pressure exerted by magma under the earth’s crust.
So, is it possible to predict volcanic eruptions? In a way, yes, and the more background information volcanologists have, the better. Factors such as knowing the eruptive history of the volcano ; be able to install the necessary instrumentation in the field ; and keeping track of volcanic activity data helps scientists be more accurate in their predictions. Still, volcanologists can only speak in terms of probabilities, but they can never be sure of the severity of the eruption or even if the magma will make it to the surface.
As it is not possible to study every point on Earth, the most common practice is to monitor the most active volcanoes and monitor the warning signs that they give in the days before the eruption:
- When magma rises through cracks in the earth’s crust, multiple small earthquakes occur on the surface. These are detected thanks to the help of seismometers.
- The temperature around the volcano increases with volcanic activity. Thermal variations can be observed in thermal satellite images.
- When the volcano is close to the eruption it begins to release gases , which the more sulfur they contain, the closer the moment of the eruption will be. The concentration of gases is measured with chemical sensors or spectrometers.
- In addition, laser technology allows us to measure changes in the shape of the mountain as the magma opens up inside it.
So while these methodologies provide us with valuable information, it is still difficult to accurately predict the time, place and duration of volcanic eruptions. However, volcanologists are not giving up and continue to search for new ways to accurately predict the awakening of these fire giants.
Einat Lev, research associate professor of seismology, geology, and tectonophysics at Columbia University’s Lamont-Doherty Earth Observatory, tells us that “the technology for acquiring pre-eruption information exists for the most part, but unfortunately, they are very few places that have enough sensors already installed. […] Only about 20% of eruptions have an appropriate increase in alert level before the eruption occurs. The eruption time can vary from hours to days or months. It often depends on the type of volcano ”.
References:
Agarwala, D. (2021, February 8). You Asked: Why Is it So Hard to Predict Volcanic Eruptions? State of the Planet. https://news.climate.columbia.edu/2021/02/09/difficult-predict-volcanic-eruptions/
