Photo of eruption at Mount Redoubt in Alaska in 2009. Credit: Game McGimsey, USGS
New research methods may lead to earlier predictions of volcanic eruptions.
Although there are telltale signs that a volcano is likely to erupt in the near future – an increase in seismic activity, changes in gas emissions and sudden soil deformation, for example – the exact prediction of these eruptions is notoriously difficult.
This is partly because no two volcanoes behave in exactly the same way and because few of the world’s approximately 1,500 active volcanoes have monitoring systems. Under the best of circumstances, scientists can accurately predict an eruption of a monitored volcano a few days before it happens. What if we knew months or even years in advance?
Using satellite data, scientists from GODMOTHERThe Southern California Jet Propulsion Laboratory and the University of Alaska, Fairbanks, have developed a new method that brings us closer to that reality. The research was recently published in Nature Geoscience is a monthly scientific journal published by Nature Publishing Group, covering all aspects of Earth sciences, including theoretical research, modeling and fieldwork. Other related papers are also published in fields that include atmospheric sciences, geology, geophysics, climatology, oceanography, paleontology and space science. It was established in January 2008.
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“The new methodology is based on a subtle but significant increase in heat emissions over large areas of a volcano in the years before its eruption,” said lead author Társilo Girona, previously JPL and now with the University of Alaska, Fairbanks. “It allows us to see that a volcano has awakened again, often long before any of the other signs appear.”
Scientists recently discovered that Mount Domuyo in Neuquen, Argentina, presented here, is an active volcano. Credit: Adobe Stock / Guillermo Cisneros
The study team analyzed 16 ½ years of radiant heat data from Moderate Resolution Imaging Spectroradiometers (MODIS) – instruments aboard NASA’s Terra and Aqua satellites – for several types of volcanoes that have erupted in the past two decades. Despite the differences between the volcanoes, the results were uniform: in the years leading up to an eruption, the radiant surface temperature on a large part of the volcano increased by about 1 degree. Celsius from its normal state. It decreased after each eruption.
“We are not talking about hot spots here, but rather the warming of large areas of volcanoes,” said JPL co-author Paul Lundgren. “So it’s probably related to the fundamental processes that take place in depth.”
In particular, scientists believe that the increase in heat can result from the interaction between magma tanks and hydrothermal systems. Magma (molten rock below the Earth’s surface) contains gases and other fluids. When it rises through a volcano, the gases diffuse to the surface and can emit heat. Similarly, this degassing can facilitate the flow of groundwater and raise the groundwater level, as well as hydrothermal circulation, which can increase soil temperature. Scientists say there may be other processes, because although understanding the behavior of the volcano is improving, it remains limited.
“Volcanoes are like a box of mixed chocolates: they can look similar, but inside there is a lot of variety between them and sometimes even inside the same one,” Lundgren said. “In addition, only a few volcanoes are well monitored, and some of the potentially dangerous volcanoes are the least eruptive, which means you can’t rely strictly on historical records.”
Combining data
The new method is significant on its own, but can provide even more information about the volcano’s behavior when combined with data from models and other satellites.
In a study published in Scientific reports Last summer, Lundgren used synthetic aperture radar (InSAR) interferometric data to analyze long-term deformation at Argentina’s Domuyo Volcano. At the time, scientists weren’t sure if Domuyo was a dormant or extinct volcano or just a mountain. Lundgren’s research quickly clarified this. He unexpectedly detected a period of inflation, which occurs when part of a volcano expands as a new mass of magma moves upward and pushes the rock out of the way. It seems that Domuyo is very much a volcano – and an active one.
Lundgren then compared this deformation time series with the Társilo Girona thermal time series created for the Domuyo volcano. Lundgren’s goal: to determine whether the two processes – an increase in both the radiant surface temperature over large areas of the volcano and the deformation – were connected.
“We found that the thermal time series mimics a lot the deformation time series, but with a certain time separation,” Lundgren said. “Even if it remains unclear what process is likely to happen first, showing the correlation, we can connect processes through physics-based interpretations, rather than simply relying on what we can observe in the footnote.”
In other words, the combination of data sets provides clues about what goes deeper inside the volcano and how different processes influence and interact with each other – data that can improve precision of models used to predict eruptions.
“Although the research does not answer all the questions, it opens the door to new approaches to remote sensing – especially for distant volcanoes – which should provide us with some fundamental information on competing hypotheses for how volcanoes behave in general dynamic terms at intervals. for several years to decades, ”Lundgren added.
Looking ahead
Going further, scientists will test the thermal time series method on several volcanoes and continue to adjust their accuracy.
“One of the goals is to one day have a tool that can be used in near real time to check for volcanic activity in volcanic areas,” Girona said. “Even for small eruptions, there is evidence of thermal disturbances before the onset of the eruption event, so the new method helps us get a little closer to this goal.”
The data help to complement the existing tools used at the monitored volcanoes. But the number of volcanoes for which life-saving data can be made is also increasing.
“Using the new thermal method that detects changes in surface temperature around volcanoes and InSAR soil surface deformation measurements helps observers of volcanoes around the word identify which volcanoes are most likely to erupt and which volcanoes should be instrumented for closer observation. , Said Lundgren. “By using satellite data, you increase the scope of what can be monitored on a regular basis.”
As for Domuyo, once largely ignored, the story is constantly evolving: it is one of the few volcanoes that have recently been prioritized by the Argentine government, being equipped with a monitoring system.
References:
“Large-scale thermal disturbances of volcanoes years before the eruption” by Társilo Girona, Vincent Realmuto and Paul Lundgren, March 11, 2021, Geoscience of nature.
DOI: 10.1038 / s41561-021-00705-4
“Dynamics of large silicon systems in satellite remote sensing observations: the fascinating case of Domuyo volcano, Argentina” by Paul Lundgren, Társilo Girona, Mary Grace Bato, Vincent J. Realmuto, Sergey Samsonov, Carlos Cardona, Luis Franco, Eric Gurrola and Michael Aivazis , 15 July 2020, Scientific reports.
DOI: 10.1038 / s41598-020-67982-8