The Hawaiian volcano Kīlauea began erupting on May 4, 2018. It wouldn’t stop until four months later, in September. The lava flows closed national parks, created new islands, and changed Hawaii’s coastline.
Now we’re learning something else about Kīlauea: Scientists at the U.S. Geological Survey (USGS) are revealing their study of this year’s eruption, and have come to the conclusion that the four-month explosion was “unprecedented.” Here’s why.
When looking at volcanoes, scientists often focus on what’s known as the caldera, a volcanic crater similar to a cauldron. When magma chambers deep within a volcano drain suddenly and unexpectedly, the caldera collapses—it’s “like a balloon deflating,” says Emily Montgomery Brown, a research geophysicist at the USGS, speaking to Popular Mechanics via email.
These collapses lead to gigantic gas releases and violent eruptions. Caldera collapses are associated with some of the most famous eruptions of all time, like Vesuvius, the disaster that buried Pompeii. “One of the big scientific questions we didn’t know regarding Kīlauea’s caldera collapse is whether the collapse would occur catastrophically (all at once), or incrementally,” says Montgomery Brown.
Kīlauea’s caldera has deflated before—in 100 years of modern monitoring, it has fallen slightly. Montgomery Brown describes most of these events as “tens of centimeters to maybe one meter.” What makes the 2018 eruption so historic was that, when all was said and done, Kīlauea’s caldera had dropped 500 meters, or around 1,640 feet. The collapse occurred incrementally, as it turned out, over 62 incidents.
“Each of those 62 almost-daily events was still larger than any of the other subsidence events we’ve measured with modern geophysical instruments,” Montgomery Brown says.
Alongside the caldera’s tremendous collapse, Montgomery Brown and her fellow USGS scientists also examined Kīlauea’s Lower East Rift Zone (LERZ). That’s where scientists have been closely monitoring to see if the volcano has any chance of erupting again. While it’s no longer currently active, the LERZ was also showing noticeably higher eruption rates. Both of these “occurring together…is what made the sequence so intriguing,” Montgomery Brown says.
This year’s powerful eruptions destroyed more than 600 homes and made Kīlauea the most destructive volcano in the United States since Mount St. Helens erupted in Washington State in 1980. A remnant of the original volcanoes that created the Hawaiian islands in the first place, Kīlauea continued the tradition by creating a small new piece of land off the coast.
The sustained Kīlauea eruption of 2018 offered a point of intrigue and fear to Hawaiian residents and tourists alike. Out of 24 injuries sustained in the eruption, 13 of them came from a boat ride full of tourists trying to get a closer look.
“Volcanoes are spectacular,” Montgomery Brown says, “and volcano-tourism is popular in Hawaii and worldwide, but it is prudent for visitors to remember that volcanoes are hazardous.”
Originally posted on Popular Mechanics