Pu’u O’o: Three-decade eruption of Kilauea yields scientific discoveries


By COLIN M. STEWART

Tribune-Herald staff writer

On a geologic scale, the last three decades have been barely a blip on the radar against a backdrop of millions of years of earth-shattering, world-building events.

But in terms of the science of volcanology, the last three decades have supplied a veritable treasure trove of opportunities to further mankind’s understanding of the forces that help shape our planet.

On Thursday, the more-or-less continuous eruption of lava emanating from Hawaii Island’s Pu‘u O‘o vent on Kilauea Volcano will turn 30 years old, marking a milestone in the work being done by scientists with the U.S. Geological Survey’s Hawaiian Volcano Observatory.

“The changes in technology over the last 30 years have allowed us to see much more and be more quantitative about measuring the changes a volcano goes through,” said Jim Kauahikaua, scientist in charge at HVO. “We know a lot more about how lava flows work, and we can, to a certain degree, predict where they go and how fast they’ll get there. … And just in the last four years, we’ve learned a lot about lava lakes — a very important piece of the puzzle.”

Kauahikaua said that he’s been studying the eruption since shortly after it began, on Jan. 3, 1983.

“I was born on Oahu and started working here in the mid-’70s as a grad student at UH-Manoa,” he said. “I was one of the people they called to come over when the eruption started.”

Initially, he said, scientists had no idea how powerful and sustained the eruption would become. Since the late 1970s, there had been a few other short-lived eruptions observed that would come and go, and scientists thought they were witnessing another one of those.

“That was the expectation at the beginning of this one,” he said. “… But as the months and years wore on, it became obvious it wasn’t one of those at all.”

The first three and a half years or so was a time of small eruptions going on and off again in fits and starts, he said, with fissures opening up and low fountains of lava being observed. But then, in mid-1986, the magma conduit beneath Pu‘u O‘o ruptured, and new fissures opened, extending 2 miles downrift from the base of the cone. This led to the easternmost fissure evolving into a single vent, named Kupaianaha. Thus began what has been nearly continuous lava flow since then, he said.

“After the mid-86 switchover, the lava’s been coming out pretty much continuously. The actual place it’s come out of the ground has changed, but it has continued,” Kauahikaua said.

Over the years, the continued activity, paired with the volcano’s accessibility on the Big Island, has served to provide scientists with plenty of opportunities to learn about how volcanoes work, he said. And while they are learning how better to predict future events, they are also becoming skilled at using knowledge gained in the last 30 years and applying it to events that occurred further back in time.

“One eruption, which we’ve named ‘Ai la‘au, happened about 450 years ago, but it was hard to pin down how long it lasted,” Kauahikaua said. “Now (using knowledge gained in part from the Pu‘u O‘o eruption), we think it may have been between 40 and 60 years.”

The last 30 years has provided plenty of exciting moments for scientists, but perhaps none as thrilling as the moment on Jan. 29, 1997, when the crater floor at Pu‘u O‘o collapsed, dropping between 450 and 500 feet overnight, and draining the massive lava lake, he said.

“It had already started to collapse in a minor way, but then, all of a sudden, the bottom fell out,” Kauahikaua said. “It left a hole as deep as it was wide. It was incredible. It was huge. I mean, we’d been visiting this area almost weekly for a long, long time, then all of a sudden, that happened. It was eery to see it from the air. To get up on the edge of it. Just the sheer size of it. It was really spooky.”

Looking toward the future of the eruption, Kauahikaua said anything is possible. It could slowly grind to a halt, or it could go another 30 years, or even longer. He and his team of scientists say they’ve got plenty of work left to do, so they hope the lava flows will continue for years to come.

One area where they hope to make breakthroughs soon is on the subject of lava lakes.

“A lot of the work going on at the observatory right now is trying to really understand in general their relation to summit eruptions,” he said. “It feels like we’re on the verge of a big discovery in that way, and it would truly be exciting. We don’t have enough data yet, and it would certainly be a shame to have the activity stop before we’ve figured it out.”

Email Colin M. Stewart at cstewart@hawaiitribune-herald.com.

January is Volcano Awareness Month

In recognition of the 30th anniversary of the Pu‘u O‘o eruption and Volcano Awareness Month, the U.S. Geological Society will host a number of talks:

Where: University of Hawaii at Hilo, University Classroom Building (UCB), Room 100

When: Thursdays at 7 p.m.

Jan. 3 — 30th Anniversary of Kilauea Volcano’s East Rift Eruption

Tim Orr, USGS Hawaiian Volcano Observatory

Jan. 10 — Looking for Lava in All the Wrong Places — and Finding It in Some

Don Swanson, USGS Hawaiian Volcano Observatory

Jan. 17 — Pelehonuamea, Volcanism

Pualani Kanaka‘ole Kanahele, Edith Kanaka‘ole Foundation and

Hawai‘i Community College

Jan. 24 - Mauna Loa: How Well Do You Know the Volcano in Your Backyard?

Frank Trusdell, USGS Hawaiian Volcano Observatory

Jan. 31 - Snowballs from Kilauea?

Ken Hon, University of Hawai‘i at Hilo Geology Department

“After Dark in the Park” Programs

Tuesdays at 7 p.m.

Kilauea Visitor Center, Hawaii Volcanoes National Park

Park entrance fees apply. More information: (808) 985-6014 or 985-6011.

Jan. 8 — 30th Anniversary of Kilauea Volcano’s East Rift Eruption

Tim Orr, USGS Hawaiian Volcano Observatory

Jan. 15 — What’s happening in Halema‘uma‘u Crater?

Matt Patrick, USGS Hawaiian Volcano Observatory

Jan. 22 — A Below-the-Scenes Look at Kīlauea Volcano’s “Plumbing” System

Mike Poland, USGS Hawaiian Volcano Observatory

Jan. 29 — The Story Behind Monitoring Hawaiian Volcanoes: How HVO Gets the Data It Needs to Track Eruptions and Earthquakes

Kevan Kamabayashi, USGS Hawaiian Volcano Observatory

 

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