May. 21, 2018
CWU Volcanologist Researches Kilauea Eruptions
For thirty years, volcanologist Wendy Bohrson has been studying the eruptions of Hawaii’s Kilauea volcano. The Central Washington University geology professor focuses on the intense magma-mixing that happens deep under the volcano.
“Kilauea has a complex magma storage system,” Bohrson explained. “We can look at the frequency and style of the mixing, based on the rock evidence from previous lava flows. As we understand more about that system, we contribute to improving eruption prediction.”
Bohrson began studying Kilauea in the 1980s when she worked for the United States Geological Survey.
“I was fortunate to be part of a team of USGS scientists that monitored the Kilauea eruptions,” she recounted. “Today, not only is magma erupting on the flank of Kilauea, but magma has been visible in a pit crater—an open crater with magma in it at the summit.”
Magma, or molten rock, is fundamental to the formation of the volcano. At Kilauea, magma can erupt at the summit, where it bubbles up from the lava lake in the caldera. But magma can also erupt on the flanks, where it surges through fissures that allow magma to move from the summit down the flank of Kilauea.
Currently, Kilauea’s magma is now flowing out of fissures and down a path in the rift zone. As the magma oozes out of the fissures down the rift, the summit starts to deflate.
Bohrson regularly takes students to Hawaii to study Kilauea and slow-moving lava flows. It’s so hot, she related, a person can barely get within three feet of the flow. Magma is almost hot enough to melt steel--about 2,100 degrees F. Her students were fascinated by the lava flowing on the coastal plain. “When students can see lava flow, features we study in lab make more sense. The hike to the active flows is tough, and so students are very excited when we actually find flowing lava!”
It was steam that caused the May 17 eruption, when the summit lava lake dropped low enough within the volcano to intersect the water table. The resulting explosion spewed ash, rocks and other debris high into the air, coating the surrounding countryside in a hard paste of ash and rain. USGS scientists expect more explosive eruptions. The last major event like this at Kilauea was in 1924.
“Our goal is to understand how Kilauea evolves as it erupts,” Bohrson said. “We look at details of crystals in the lava rocks to understand how magma changes before and during an eruption. We also use computational tools to help us quantify Kilauea’s magma storage reservoir. We want to know how big magma storage system is, and the frequency and style of magma-mixing. We want to add to our knowledge about what types of eruptions might occur and when they might occur.
“Our end goal is to help improve eruption prediction, and thus lessen the dangers of volcanic eruptions.”
Photo 1 -- Recent Kilauea activity, courtesy of the USGS
Photo 2 -- A group of Bohrson's students in Hawaii, studying the Kilauea lava flows
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