STAR-BULLETIN FILE Differences in lava samples taken from Halemaumau crater and Puu Oo vent on Kilauea suggest the system moving lava under the volcano is more complex than originally thought.

Lava differences unveil complexities of Kilauea

Samples from various areas have differences that could hint at a more complex system

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University of Hawaii at Manoa scientists have found differences between lava taken from the recent eruption at Halemaumau crater and lava from Puu Oo vent.

The differences suggest the "plumbing" under Kilauea might be more complicated than first thought.

"If there's a difference, it means some other processes are going on," said UH-Manoa geologist-geophysicist Michael Garcia.

Garcia is still confirming his findings. But he said the recent activity at Kilauea's summit are giving scientists the first opportunity in 26 years to look at how magma moves to the volcano.

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The long-standing view has been that lava is rising from a magma reservoir under the summit and moving about 20 miles through the east rift zone to the Puu Oo vent, said Michael Garcia, University of Hawaii geologist-geophysicist.

"We think it is more complicated than that. Previous studies also suggested the system is much more complicated than that," he said.

Garcia said his lab analyzed lava samples collected from Puu Oo and during the three major explosions at the summit on March 23, April 9 and April 14.

This year's summit eruption was the first opportunity in 26 years to look at how magma moves to the volcano, he said. The last eruption there was in September 1982.

"We're waiting for another opportunity to sample it," he said. "It's not like crawling under a house to look at the plumbing. We have to use the lava to test chemistry as a tool to learn how lava moves to the mantle through the volcano and gets to the surface.

"We are finding differences," he said, cautioning that his lab is investigating to see whether the samples might be contaminated.

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"Puu Oo samples change very, very slowly with time," he said. "The summit samples seem to change rapidly. We're trying to see how the two compare and what it tells us about how magma is being stored in the volcano and whether there is a good connection between the summit reservoir and magma feeding the rift zone."

"Garcia noted pulsing activity going on now at the summit, with brighter glows every six to seven minutes. "The idea is gas is able to form separate bubbles within the magma, comes out and forms a big bubble and bursts.

"It forces the lake or pond inside the crater to rise and then go down. ... It may mean something may happen in the future."

"Paul Okubo, Volcano Observatory geophysicist-seismologist, said there is "a traditional view that lavas that erupt in the rift zone in some manner migrate somewhat vertically from the mantle into the summit caldera."

"But he said this is "a working model," subject to new observations and data. "We're getting some new things to look at now with Halemaumau being active and Puu Oo still active in a recent path that's been unusual."

"Scientists need to understand "what may or may not be involved" if there is a magma path for Puu Oo that's distinct from the one delivering lava to the summit caldera, Okubo said.

"It is an extremely complex system, and we kind of depend on activity and being able to track the activity to try to understand what some of the complexity is," he said.

Garcia said his lab has a collection of lavas from many eruptions over the years at the summit and at rift zones, and one of his students is testing them.

"The question is, how do they compare?" he said. "Are they similar or different? We're trying to test how magma moves to the volcano."