A new warning sign to predict volcanic eruptions?

Satellite imagery can help better predict volcanic eruptions by monitoring changes in surface temperature near volcanoes.

Volcano erupted lava volcanic sky active rock night ecuador landscape

Volcano erupting lava, volcanic sky active rock night Ecuador landscape

Credit: Ammit via Adobe Stock
  • A recent study used data collected by NASA satellites to conduct a statistical analysis of surface temperatures near volcanoes that erupted from 2002 to 2019.
  • The results showed that surface temperatures near volcanoes gradually increased in the months and years prior to eruptions.
  • The method was able to detect potential eruptions that were not anticipated by other volcano monitoring methods, such as eruptions in Japan in 2014 and Chile in 2015.

How can modern technology help warn us of impending volcanic eruptions?

One promising answer may lie in satellite imagery. In a recent study published in Nature Geoscience, researchers used infrared data collected by NASA satellites to study the conditions near volcanoes in the months and years before they erupted.

The results revealed a pattern: Prior to eruptions, an unusually large amount of heat had been escaping through soil near volcanoes. This diffusion of subterranean heat — which is a byproduct of "large-scale thermal unrest" — could potentially represent a warning sign of future eruptions.

large-scale thermal unrest Conceptual model of large-scale thermal unrestCredit: Girona et al.

For the study, the researchers conducted a statistical analysis of changes in surface temperature near volcanoes, using data collected over 16.5 years by NASA's Terra and Aqua satellites. The results showed that eruptions tended to occur around the time when surface temperatures near the volcanoes peaked.

Eruptions were preceded by "subtle but significant long-term (years), large-scale (tens of square kilometres) increases in their radiant heat flux (up to ~1 °C in median radiant temperature)," the researchers wrote. After eruptions, surface temperatures reliably decreased, though the cool-down period took longer for bigger eruptions.

"Volcanoes can experience thermal unrest for several years before eruption," the researchers wrote. "This thermal unrest is dominated by a large-scale phenomenon operating over extensive areas of volcanic edifices, can be an early indicator of volcanic reactivation, can increase prior to different types of eruption and can be tracked through a statistical analysis of little-processed (that is, radiance or radiant temperature) satellite-based remote sensing data with high temporal resolution."

Temporal variations of target volcanoes Temporal variations of target volcanoesCredit: Girona et al.

Although using satellites to monitor thermal unrest wouldn't enable scientists to make hyper-specific eruption predictions (like predicting the exact day), it could significantly improve prediction efforts. Seismologists and volcanologists currently use a range of techniques to forecast eruptions, including monitoring for gas emissions, ground deformation, and changes to nearby water channels, to name a few.

Still, none of these techniques have proven completely reliable, both because of the science and the practical barriers (e.g. funding) standing in the way of large-scale monitoring. In 2014, for example, Japan's Mount Ontake suddenly erupted, killing 63 people. It was the nation's deadliest eruption in nearly a century.

In the study, the researchers found that surface temperatures near Mount Ontake had been increasing in the two years prior to the eruption. To date, no other monitoring method has detected "well-defined" warning signs for the 2014 disaster, the researchers noted.

The researchers hope satellite-based infrared monitoring techniques, combined with existing methods, can improve prediction efforts for volcanic eruptions. Volcanic eruptions have killed about 2,000 people since 2000.

"Our findings can open new horizons to better constrain magma–hydrothermal interaction processes, especially when integrated with other datasets, allowing us to explore the thermal budget of volcanoes and anticipate eruptions that are very difficult to forecast through other geophysical/geochemical methods."

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