NASA scientists believe it may be possible to predict when a volcano will erupt by using satellites to track changes in the color of surrounding trees.
Before volcanoes erupt, they begin seeping carbon dioxide, a cue that people living nearby should evacuate. When, in December 2017, carbon dioxide levels began to rise around the Mayon volcano in the Philippines, officials alerted the public. More than 56,000 people evacuated, and after the volcano blew in January, not a single life was lost.
The challenge is that many volcanoes are so remote that it is costly, challenging, and potentially dangerous to set up monitoring equipment on site, and the volume of carbon dioxide seeping from volcanoes is too small to be detectable by satellites. However, scientists have found that even small amounts of carbon dioxide can affect the growth of nearby trees, causing their foliage to become greener and more lush, and that these changes are visible from space.
A recent study found a link between tree color, as shown in satellite imagery, and the amount of carbon dioxide issuing from Mount Etna, an active volcano in Italy. Now, NASA is studying changes in trees around the Rincón de la Vieja Volcano in Costa Rica in the hope of better predicting eruptions.
Experts already have other forecasting tools. Before an eruption, the ground around a volcano bulges as magma rises beneath the surface, while small tremors hint that disaster is imminent. Recent research found that glaciers atop volcanoes flow faster as the earth heats up. Greening offers just one more clue.
“There’s not one signal from volcanoes that’s a silver bullet,” said NASA volcanologist Florian Schwandner. “And tracking the effects of volcanic carbon dioxide on trees will not be a silver bullet. But it will be something that could change the game.”
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