Extreme rainfall can trigger more volcanic eruptionsDate: 27 April 2020 Tags: Geography & Environment
The May 3, 2018 eruption of Hawaii’s Kilauea volcano caused large damage. Researchers think that extreme rainfall in preceding months could have triggered the volcanic eruptions.
As the planet heats up, extreme rainfall events are likely to become more frequent, and bigger ice sheets will melt. Those events could trigger not just volcanoes but earthquakes and tsunamis.
Volcanic rocks in Hawaii are permeable, which makes it easy for rainfall to seep and increase groundwater levels quickly. The rapid increase creates pressure that can propagate for several kilometres underground.
With enough rain, the stress could cause fractures in the rocks holding back volcanic lava, just as melting ice sheets have been shown to relieve pressure and trigger volcanoes in a similar fashion.
Researchers on the new study used satellite data from NASA and Japan’s space agency to estimate rainfall during the first months of 2018, before the start of the eruption.
On April 14 and 15, the area near the volcano received about 4 feet of rain, more than what Hurricane Maria dumped on Puerto Rico.
In the weeks after, underground pressure increased to its highest level in almost 50 years. Collection of subsurface water and pressure data isn’t always part of volcano monitoring, but the study makes the case that it should be.
They created a model to show how the accumulated rainfall could seep into the pore spaces in rocks deep underground, boosting pressures that eventually caused fissures in the volcano’s flank to open up and release magma.
It’s not the first time rainfall has been linked to volcanic activity. Previous research suggests storms passing over Mount St. Helens may have played a role in explosive activity between 1989 and 1991.