Extreme rainfall triggered the 2018 Kilauea eruption

Extreme rainfall triggered the 2018 Kilauea eruption. Excessive and persistent rainfall initiated the Kīlauea volcano eruption of 2018, according to a new study from the University of Miami Rosenstiel School of Marine and Atmospheric Science.

The researchers found that just before the Kīlauea eruption, fluid pressure was at its highest in nearly five decades. The immense pressure likely facilitated the movement of magma beneath the volcano.

“We knew that changes in the water content in the Earth’s subsurface can trigger earthquakes and landslides. Now we know that it can also trigger volcanic eruptions,” said study co-author Professor Falk Amelung. “Under pressure from magma, wet rock breaks easier than dry rock. It is as simple as that.”

On May 3, 2018, Kīlauea experienced an explosive and widespread eruption that lasted for months. Lava was thrown up to two hundred feet in the air, destroying hundreds of homes and scorching the landscape across the eastern coast of Hawaii’s Big Island.

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

The UM researchers used rainfall measurements to estimate the fluid pressure that had built up within the volcano’s structure prior to the eruption. 

Professor Amelung said the research was made possible by using data from a number of Earth-observing satellites. “We obtained precipitation information from a joint mission between NASA and the Japanese Space Exploration Agency and ground deformation observations from a mission of the European Space Agency.”

The study revealed that immediately before and during the Kilauea eruption, an unusually large amount of cumulative rainfall increased pore pressure within the rift zone to its highest point in almost 50 years. 

“Interestingly, when we investigate Kīlauea’s historical eruption record, we see that magmatic intrusions and recorded eruptions are almost twice as likely to occur during the wettest parts of the year,” said study lead author Jamie Farquharson.

The findings suggest that local rainfall patterns may contribute significantly to Kīlauea eruptions, and this is likely to be the case with other volcanoes as well.

“Having established the evidence for rainfall-triggered eruptions at Kīlauea, it will be fascinating to investigate other volcanoes,” said Farquharson. “If we can identify regions of the globe where this kind of coupling between rainfall and volcanism exists, it could go a long way towards advanced warning of associated volcanic hazards.”

“It has been shown that the melting of ice caps in Iceland led to changes of volcanic productivity. As ongoing climate change is predicted to bring about changes in rainfall patterns, we expect that this may similarly influence patterns of volcanic activity.”

The study is published in the journal Nature.

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By Chrissy Sexton, Earth.com Staff Writer