Kilauea eruption will fuel volcano research for years to come
  • Thursday, November 15, 2018
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Hawaii News

Kilauea eruption will fuel volcano research for years to come

  • U.S. GEOLOGICAL SURVEY

    A Hawaiian Volcano Observatory geologist collected samples of spatter for analysis in Leilani Estates on May 6.

  • U.S. GEOLOGICAL SURVEY

    Hawaiian Volcano Observatory scientists measured fountain heights and took high-resolution video Friday to determine whether the volume of material exiting the vent had changed.

  • U.S. GEOLOGICAL SURVEY

    An unidentified Hawaiian Volcano Observatory geologist checked cracks May 17 on Nohea Street in Leilani Estates that had expanded significantly from the previous day.

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It didn’t take long for Kilauea to start spitting out clues to the ongoing mystery of what lies beneath Hawaii’s youngest and most active volcano.

As thick, chunky lava oozed from the first of two dozen vents that have opened in Lower Puna on Hawaii island in the first stages of the 5-week-old eruption, scientific analysis revealed a geochemical fingerprint of the early flows that closely matched output from decades-old eruptions.

“This raises new questions about the connection between the summit and the East Rift Zone, and where and how much magma is stored in the rift zone,” said USGS research geophysicist Kyle Anderson, who is in Hawaii as part of the federal agency’s eruption response team.

After producing more than 10,000 earthquakes, 250-foot-high lava fountains and summit explosions that sent plumes of steam and ash 30,000 feet into the air, Kilauea continues to behave in ways that are surprising even to longtime volcano observers, as it provides grist for scientific research for years to come.

“This is certainly a global learning moment for our scientists on the ground here and within the scientific community. It’s being called a generational event,” said volcanologist Wendy Stovall, who normally works out of Cascades Volcano Observatory in Vancouver, Washington, but has been on Hawaii island since soon after the eruption began.

With Kilauea’s every outbreak, ground movement, tremor and emission recorded with sophisticated tools, “combing through all of that data will be a life’s work,” she said. “This is going to be an ongoing thing with new findings and publications by the end of this year.”

Stovall and Anderson, who is assigned to the California Volcano Observatory in Menlo Park, are part of a contingent of 80 USGS personnel in Hawaii to study the Kilauea eruption. An additional 10 to 15 scientists are working remotely from the Alaska Volcano Observatory and elsewhere, Stovall said.

“We’re working as a team,” she said. “Alaska has a volcano that fires ash and this is a new thing for Hawaii. We’re working closely with them.”

Even before the ground cracked open and magma pushed to the surface in the rural Leilani Estates subdivision on May 3, Kilauea was one of the most closely monitored volcanoes in the world.

Under normal circumstances, the 30 USGS scientists stationed at the Hawaiian Volcano Observatory overlooking the summit caldera would be spending their days collecting and analyzing data from visual observations and more than 100 field instruments, including tiltmeters, seismic and deformation stations, as well as thermal cameras, GPS, satellite radar and other high-tech tools that record earthquakes, ground movement, gas emissions, sound waves, magma volume and movement, lava flows and other volcanic processes.

Although USGS staff were evacuated from the HVO and some web cameras and monitoring tools were lost in a May 17 explosion at the summit, many of the instruments are still operating and new ones have been installed.

Since the start, Stovall said, scientists have been concentrating on tracking moment-to-moment changes in volcanic activity in the lower East Rift Zone to guide emergency operations by Civil Defense and public health and safety agencies. The work includes measuring temperatures and steam where the earth has split open to predict new outbreaks and collecting fresh samples of 2,000-degree lava to analyze its source and composition.

“It hasn’t happened very often that you have fissures erupting in such a dynamic manner,” she said.

Excitement at dual activity

Kilauea’s Puu Oo vent in the East Rift Zone has been producing lava continuously since 1983 but has been relatively quiet in recent years. What has scientists excited about the current event is the dual activity — lava flows and vigorous fountains in the rift zone and expansion, deflation, earthquakes and explosions at the summit — that hasn’t been seen since before many of the scientists on site were born.

“The fact that there are two very different eruption styles going on simultaneously is surprising, more so just because I didn’t know I would ever experience this kind of thing,” said geologist Scott Rowland, who is watching developments from the University of Hawaii at Manoa’s School of Ocean and Earth Science and Technology.

“Geologically, it’s not so much a surprise, since something like this has happened before. The Puna eruption in Leilani Estates that is producing the flows inundating Kapoho is somewhat similar to what happened in 1955 and 1960, and the summit activity, with magma leaving the region, causing the lava lake to drain away, and Halemaumau expanding and the small explosions happening there, is similar to what happened in 1924,” he said.

“But we have not gone through both styles simultaneously.

“The fact that there is current summit and flank activity is really going to help us and USGS have a better understanding of how the different parts of the volcano can work together and how the plumbing system works. We are really going to be able to learn a lot once the crisis is over and people can catch their breath.”

Rowland, who has studied old lava flows at Kilauea, said he’s hoping the data will bolster research into whether there is a pattern between eruptions on the rift zone and “lots of action on the summit.”

Implications for other volcanoes

FIRST DAYS OF THE 2018 KILAUEA ERUPTION

>> April 26: Large overflow onto Halemaumau crater floor at summit as lava lake rises.
>> April 30: Puu Oo crater collapses on East Rift Zone, causing deformation downrift of the vent and increased seismicity as far east as Highway 130 in Lower Puna.
>> May 1: Summit deflation begins; USGS issues advisory of likely eruption in lower East Rift Zone.
>> May 2: First small ground cracks open in and adjacent to Leilani Estates; lava lake begins to drop.
>> May 3: Magnitude-5.0 earthquake causes additional collapse at Pu‘u ‘O‘o. Eruption commences with fissure opening in area of Mohala and Leilani streets in Leilani Estates.
>> May 4: Five more vents become active; 6.9-magnitude earthquake produces ash plume at Puu Oo.
>> May 5: Three more vents open, with Fissure 8 fountaining and building a spatter cone.
>> May 17: Explosive eruption occurs at summit, with 30,000-foot ash cloud; a total 22 fissures have opened in Leilani Estates and Lanipuna Gardens (current total is 24).

Source: U.S. Geological Survey

Fed by molten rock erupting from a “hotspot” in the sea floor, Hawaii’s gently sloping shield volcanoes are vastly different from steeper stratovolcanoes with more-viscous magma that plugs up their inner plumbing, allowing gas pressure to build, leading to violent, explosive eruptions such as those seen at Mount St. Helens in Washington, the Philippines’ Mount Pinatubo and this month’s Fuego eruption in Guatemala that has killed at least 100 people.

Scientists say research generated from the current Kilauea activity could have implications for understanding comparable volcanoes around the world. Stovall noted similarities between the Hawaii event and eruptions at the Grimsvotn volcano in Iceland and Russia’s Kamchatka Peninsula in 2011 and 2017, respectively, that sent steam and ash miles into the atmosphere.

Closer to Hawaii, Oregon State University geology professor Adam Kent said he is following the Kilauea eruption with nearby mountains in mind.

“We have a lot of volcanoes in Oregon and the Pacific Northwest that produce different types of magma and have steeper sides, but we also have some shield volcanoes that are not that different from Kilauea or Mauna Loa,” he said.

“When you look at them, you see eruptions that probably look very similar, with eruptions from fissures and cinder cones that form and lava flows.”

Take the Newberry volcano near Bend, Oregon, Kent said.

“If an eruption happens there like the one in Kilauea, it will be just as disruptive to an area that’s growing really quickly with a lot of infrastructure,” he said. “There was a similar eruption 7,000 years ago, which sounds like a long time, especially when compared to Kilauea, but in geological terms it’s not very long at all.

“It will probably erupt again in the future, maybe not in my lifetime, but it could look very similar.”

Kent, who studies geochemistry and igneous rock, has been intrigued by the older, silica-rich andesite detected in early Puna intrusions, which “is quite rare for Hawaii,” where lower-silica basalt is the norm. The USGS has said the findings suggest the magma had been sitting in the volcano’s East Rift Zone for a long time — perhaps since the 1924 eruption — slowly crystallizing.

“It’s older magma stored in the rift zone for decades that was pushed out by new magma from the summit,” Kent said. “It sounds like magma can be stored for a long time, even along a rift zone, and be remobilized.”

Studying vog impacts

Volcanic emissions — including those commonly known as vog — and their impact on public health, agriculture and the environment are of particular interest to USGS research chemist David Damby, who is on Hawaii island on loan from the Menlo Park observatory.

Since joining the agency two years ago, he has been working with a wider network of research pulmonologists and other scientists to investigate asthma rates on the island, develop models for vog patterns and study longer-term impacts.

“There aren’t that many people and places in the world that experience vog, so this is an opportunity to have international attention on the issue of vog that is definitely going to push the research forward,” Damby said.

Working in conjunction with the Environmental Protection Agency, NOAA, the National Park Service, the state Department of Health, Civil Defense and other agencies, Damby said field crews have been taking air samples and measurements so their data, combined with readings from stationary monitoring equipment, can be used to feed the Hawaii Interagency Vog Information Dashboard (vog.ivhhn.org) and alert first-responders to drifting noxious fumes so they can provide extra support in vulnerable areas.

“The initial part of all this was very crisis response rather than scientific curiosity,” he said. “Our immediate efforts have been to apply all things we’ve learned in past years to this situation.

“But we’re almost at the point where we’ve collected enough response data that we can start to piece some things together and start systematic scientific analysis to come up with theories.

One surprise so far: “We didn’t expect it to produce as much ash as it has,” according to Damby. “It’s not very much in comparison to other volcanoes around the world, but there’s been a large amount of ash for an eruption here in Hawaii.”

Photos: Building Aloha in Puna by Honolulu Star-Advertiser on Scribd

Surprises at the summit

Scientists say most of the surprises have been coming at the Kilauea summit.

In late April, magma repeatedly overflowed onto the Halemaumau crater floor, followed by the collapse of the Puu Oo vent. The level of the lava lake dropped significantly and at one point even disappeared from view at more than 1,070 feet below the crater floor, according to the USGS.

The activity indicated magma was moving from the summit reservoir into the lower East Rift Zone, where vents opened in and around Leilani Estates in early May.

The deflation at the summit triggered shallow earthquakes, including a 6.9-magnitude shake on May 4. When the lava lake dropped below the water table, groundwater mixed with the hot rock to launch steam-driven explosions that produced major ash clouds.

According to the USGS, small explosions with ashfall from the Kilauea summit are not new, but the mechanism, intensity, plume heights and extent of ash fallout signaled a new type of eruption at the summit.

“We were all pretty awestruck by any one of these things, but put it all together and it’s pretty unprecedented,” Anderson said. “We’ve known for a long time that Kilauea can have an explosive eruption mechanism, but it hasn’t happened a lot and we didn’t have a lot of data.

“The observations coming from this will lead to research projects for years, if not decades, to come.”

He said scientists believed explosive eruptions were driven largely by interaction between water and molten rock. “That may still be true, but magmatic gas may play an important role,” Anderson explained.

“The jury is still out, and this may cause us to re-evaluate that.”

The unknowable

Those studying the current Kilauea eruption are benefiting from advanced technology and staffing not available during corresponding events in 1924, 1955 and 1960.

“This is an opportunity to understand this volcano that in some ways is unprecedented,” Anderson said. “The Hawaiian Volcano Observatory has been here more than 100 years and the technology has changed tremendously and there are new ways to monitor Kilauea. The volcano has been erupting for more than 30 years and we’ve learned a lot from that, but there are some limitations to having a fairly stable, long-term eruption.”

He said scientists have been using new technology and techniques to track the depth of the Halemaumau lava lake, plume heights and ashfall particles. Drones have been essential to mapping lava flows and are providing dramatic images to the delight of researchers, the news media and amateur volcanologists worldwide.

“This may be really the coming of age of drone technology being able to collect data from dangerous and inaccessible areas relatively cheaply and with minimal danger to people,” Kent said.

Anderson said satellite radar is providing ground-motion data on the summit’s structure, and when the lava lake dropped out of sight, photos taken from multiple angles via a helicopter allowed a USGS researcher for the first time to build a 3-D model of the geometry of the vent.

“This was really the best opportunity to see into the ground in the lava lake,” he said.

Even with all the advanced science and staff mobilized to document and study the Kilauea eruption, many questions about the volcano will remain unanswered, at least for now.

Although increased seismic activity, ground movement and other signs can alert scientists to imminent eruptions, longer-term forecasts are near impossible.

“It’s very difficult to look at a volcano and put a date on a calendar when it will erupt next, just like it’s impossible to predict earthquakes,” Kent said. “You can look at what it’s done in the past and how frequently it’s erupted, but we don’t really know what’s going on underground.”

And what about the most pressing question on the minds of volcano watchers: When will Kilauea fall silent again?

Studying previous eruptions most similar to the current one may provide some clues, according to Rowland. He noted that major East Rift Zone events in 1840, 1955 and 1960 lasted 26 days, 88 days and 36 days, respectively. Today marks the 39th day since lava came out of the ground at Leilani Estates.

The longest of those three previous eruptions lasted just shy of three months, “and that’s the ballpark we’re looking at as opposed to many months or years,” Rowland said.

“I don’t think it’s knowable with much precision. The longest eruption at the summit lasted 70 years. The current one down in Puna is very different, and I don’t think there’s any reason to think it would last that long.”

Rowland made a rough calculation of the volume of lava produced by the current eruption, based on the area covered as of Tuesday, when he was interviewed, and assuming an average thickness of 4 meters (or roughly 13 feet), since the flows are too fresh to have been measured yet to any great degree.

He estimated the Leilani Estates flows had put out 84.5 million cubic meters of lava, less than the eruptions of 1840 (205 million cubic meters), 1955 (87.6 million cubic meters) and 1960 (113.2 million cubic meters).

“The margin of error is big, but at least so far the amount of lava is not some crazy number,” he said.

“I think magma is still being supplied from the hotspot so it’s not shut off, but clearly all eruptions come to an end, and that’s the question everyone wants to know the answer to.”

In its social media posts — another relatively recent tool employed by USGS scientists — the agency stated it’s possible the Leilani Estates eruption will become a new long-term vent, like Puu Oo.

“We can’t say for sure. Past eruptions in this area have lasted weeks to months, and the pressure drawdown for the summit is rapid, so we suspect that at some point the summit will no longer be able to feed magma into the rift zone and the eruption will stop — weeks to months seems about right for the timescale of that process, but we can’t say for certain,” said a May 25 Facebook post.

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