Heavy rains may have caused the explosive eruption of Kilauea in 2018



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Lava leaving Kilauea fissure 8 on June 25, 2018.

Lava leaving Kilauea fissure 8 on June 25, 2018.
Image: USGS

Scientists attribute the Kilauea Eruption 2018, which destroyed hundreds of homes on the Big Island of Hawaii, to a surprising source: heavy and sustained rains.

According to new rainfall in the months leading up to the eruption, rocky support structures collapsed near the caldera’s magma chamber, causing lava to creep and burst on the surface, according to a new investigation published Wednesday in Nature.

The study, co-authored by geologist Jamie Farquharson of the University of Miami, proposes a new way of predicting the timing and frequency of volcanic eruptions at Kilauea and other volcanoes. That said, excessive rain is one of many possible triggers that lead to an eruption, so this is not a crystal ball.

The 2018 Puna Baja eruption it started beginnings of May. Giant cracks opened up along the Kilauea East Rift Zone, pumping alarming volumes of liquid rock Local residents, threatened by toxic fumes and invasive lava, had to flee their homes. When it was over about four months later, hundreds of structures were destroyed and the The Hawaiian coast was remade.

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That rain can influence both seismic activity and volcanoes is something that scientists had previously consideredBut these effects were only known to influence areas close to the surface. The new document is important because it suggests that rain may disturb deeper structures below.

“We knew that changes in the water content in the Earth’s subsoil can cause earthquakes and landslides. Now we know that it can also cause volcanic eruptions, ”said Falk Amelung, co-author of the study and geophysicist at the University of Miami, in a press release. “Under the pressure of magma, wet rock breaks more easily than dry rock. It’s as simple as that “.

Ash plumes during the Kilauea eruption as seen from space, as seen along the south coast.

Ash plumes during the Kilauea eruption as seen from space, as seen along the south coast.
Image: POT

The immediate cause of the Kilauea eruption in 2018 is unknown, prompting Farquharson and Amelung to investigate the potential of precipitation as a contributing factor. Using satellite and terrestrial data, the authors reported what the document describes as “Abnormally high precipitation” in the months before the eruption.

According to the research, much of this water dripped through the volcano’s underground layer due to porous volcanic rocks. This had the effect of weakening the rocks and increasing the pressure of the groundwater deep below the surface and in the areas surrounding the magma chamber. Using models fueled by acquired precipitation data, the authors showed that pressures near the chamber before the 2018 eruption were the highest in half a century.

This fluid pressure served to weaken the volcano, causing deep structural failure. The magma made its way through the weakened rocks, rising upward until it pierced the surface, according to this interpretation.

Interestingly, this theory also explains why there was no significant rise in the volcano in the months leading up to the eruption.

“An eruption occurs when the pressure in the magma chamber is high enough to break the surrounding rock and the magma travels to the surface,” said Amelung. “This pressurization causes soil inflation by tens of centimeters. Since we did not see any significant inflation in the year prior to the eruption, we started to think of alternative explanations. “

The authors also performed a Historical analysis of Kilauea, looking at archived data from rains and eruptions dating back to 1790. They found that almost 60 percent of eruptions occurred during the rainy season, which is shorter than the dry season.

Lava flowing from an active vent during the Kilauea eruption in 2018 ..

Lava flowing from an active vent during the 2018 Kilauea eruption.
Image: USGS

Write in a news and opinions that accompany it The article, planetary scientist Michael Manga from the University of California, Berkeley, said the new theory is plausible, but it should be taken with a grain of salt given the complexity and multifaceted nature of volcanic activity.

“The pressure changes calculated by their models are small, smaller than the tidal stresses,” he wrote. “However, if the rocks are close to breaking already, those changes may be enough to initiate the fault.”

As for whether fault faults can stem from changes in water pressure, that “remains uncertain,” Manga said. He continued:

“[The] FThe first magma to erupt from the lower eastern rift zone in 2018 was old, perhaps left over from a previous 1955 eruption, implying that the rift zone was already hot. As a result, the groundwater in the crack area could have been vapr at shallow depths, and at greater depths it could have been a supercritical fluid (a substance that is not in a different liquid or gas phase, but has properties of both). The high compressibility of both vaporsSupercritical fluids and rs would dampen the magnitude of pressure changes in the authors’ model, making failure less likely. “

Manga believes the new theory can be tested by looking at other archival data to see if similar patterns emerge in other volcanoes. If confirmed, it’s still a big “yes” at this point, new research could highlight aAppreciated signal to forecast the timing and frequency of volcanic eruptions.

This is a pertinent research question given the ways that climate change is already increasing the odds of heavy rains in many places. Fellow Hawaiian island Kauai for example select the US daily rainfall record USA the month before Kilauea began to erupt. So isfreaks out, but global warming could contribute to increased volcanic activityA possibility not missed for researchers.

“Melting ice sheets in Iceland have been shown to cause changes in volcanic productivity,” Farquharson said. “As ongoing climate change is expected to cause changes in rainfall patterns, we hope that this can similarly influence patterns of volcanic activity.”

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