Kilauea volcano on the island of Hawaii continues to erupt, creating spectacular footage of lava shooting out of vents and eating cars. While the lava flows are slow moving, and so far no one has been hurt, U.S. Geological Survey scientists were today (May 10) warning that the volcano might erupt explosively, sending large rocks flying through the air.
Kilauea last erupted in this way in May 1924, when a series of explosions sent rocks, dust and ash high into the atmosphere. Several people were injured by falling debris and one was killed. An earlier eruption in 1790 may have killed at least 80 people.
UC Davis volcanologist Kari Cooper, professor in the Department of Earth and Planetary Sciences, took part in a discussion about Kilauea on Minnesota Public Radio yesterday with geologist and Congressional candidate Jess Phoenix and host Kerri Miller.
While Kilauea is considered an explosive volcano, it ranks relatively low on a scale of risk because of the relatively small amount of material that could be ejected, Cooper told MPR.
A snow cone, but hot
Cooper is interested in how the magma reservoir that fuels a volcano gets into an “eruptible” state. For an eruption to occur, magma has to be mobile enough to flow to the surface. Cooler magma crystallizes into a more solid form.
The popular view of magma might be a seething pool of molten rock. But in fact the magma is generally a cooler (but still pretty hot) and more solid, Cooper has found. It’s more like a snow cone: mostly solid crystals with a little liquid seeping through it.
Magma reservoirs are difficult to reach directly, so Cooper and colleagues learn about them by studying rocks and crystals deposited around volcanos by previous eruptions. These crystals may have resided for thousands of years in a magma reservoir before being erupted. Chemical traces in the crystals allow the geologists to measure both their age and whether they have been exposed to high temperatures.
In 2014 Cooper and Adam Kent at Oregon State University, working at Mount Hood, showed that the volcano’s magma reservoir was in an eruptible state for only about 10 percent of the time and possibly as little as one percent. They found similar results with a study of Mount Tarawera in New Zealand, published in 2017.
The exciting thing in volcanology now is that forecasting is moving forward, Cooper told MPR.
“We’re moving towards a state where we make probabilistic forecasts, like a weather forecast, but we’re not there yet,” she said.
What we can learn from the Mt. Kilauea eruption (Minnesota Public Radio)
Mount Hood study suggests volcano eruptibility is rare (UC Davis News)
Volcanic Crystals Give a New View of Magma (UC Davis News)