Kīlauea Volcano’s summit eruption in Halema‘uma‘u Crater turns 7 soon
The following is an excerpt from this week’s edition of the USGS Hawaiian Volcano Observatory‘s Volcano Watch, with tips on viewing the Halema‘uma‘u eruption within Hawai‘i Volcanoes National Park provided by park rangers.
While Kīlauea Volcano’s East Rift Zone eruption at Pu‘u ‘Ō‘ō has been making headlines with the June 27th lava flow and its hazards, Kīlauea’s summit eruption within Halema‘uma‘u Crater has steadily continued in the absence of much press. However, the lack of media attention does not reflect on the eruption’s remarkable nature.
Kīlauea’s ongoing summit eruption began on March 19, 2008, after several months of increasing seismic tremor and gas emissions. A small “throat clearing” explosion opened a new crater (informally called the Overlook crater, because it is located immediately below the former National Park visitor overlook) on the wall of Halema‘uma‘u Crater. During 2008–2009, lava was only occasionally seen deep within this crater and was often masked by thick volcanic fume. In February 2010, however, lava rose within the Overlook crater and established a large lava lake that has persisted to today.
When the Overlook crater first opened, it was about 35 m (115 ft) wide, but today, it is 170 m by 220 m (560 ft by 720 ft) in size. This enlargement is the result of frequent collapses of the crater walls, some of which have dropped rocks directly into the lava lake, triggering small explosions of lava spatter and gas.
Unlike the East Rift Zone eruption which sends lava flows out onto the slopes of Kīlauea, the summit eruption emits primarily gas, along with a tiny amount of ash and fine particles (for example, Pele’s hair). To date, the lava within the summit vent has not flowed out of the Overlook crater. Instead, lava rises into the lake, releases gas and cools, and then sinks back into the magmatic system in a process called “magmatic convection.”
This containment within the crater lowers the risk posed by the lava itself, but the summit eruption creates a different kind of hazard that has a much farther reach than any lava flow. The continuous gas emissions create volcanic air pollution, commonly called “vog,” which affects communities and agriculture in downwind areas, sometimes statewide. Vog is a respiratory irritant that can cause coughing, sore throats, and headaches in otherwise healthy individuals, and can aggravate symptoms in people with pre-existing ailments, such as asthma and chronic obstructive pulmonary disease. The agricultural industry, particularly in the Ka‘ū District on the Island of Hawai‘i, has been hit hard by vog, which has damaged crops and corroded fences and other metal infrastructure.
Geologically, the Kīlauea summit eruption stands out for the size of the lava lake it has created. The lava lake in Halema‘uma‘u is most likely the second-largest lava lake on Earth, exceeded only by the lava lake in Nyiragongo Volcano in the Democratic Republic of the Congo. There are a few other—and much smaller—lava lakes on Earth, but the Halema‘uma‘u and Nyiragongo lava lakes are in a class of their own.
The expansive size of the lava lake in Halema‘uma‘u also translates to copious amounts of emitted heat. A recent study by University of Hawai‘i Mānoa researchers used satellite thermal images to calculate heat output from many of the Earth’s active volcanoes over the past 15 years, and Kīlauea—counting the summit and East Rift Zone eruptions together—was at the top of the list. The researchers state that Kīlauea’s top rank in heat output justifies its unofficial title as the most active volcano on Earth.
It’s not clear how long Kīlauea’s summit eruption will last, but recent monitoring indicators show no signs of it slowing down—or speeding up. Overall, the eruption has been characterized by a remarkable degree of steadiness. Halema‘uma‘u Crater hosted a nearly continuous lava lake for at least 100 years (first written accounts are from the early 1800s) through the early 1900s, a testament to the potential for long-lasting eruptions at the summit of Kīlauea.
Is it possible that Kīlauea Volcano’s current summit eruption will persist for decades, as it did a century ago? No one knows for sure, but if it does, we will all have to continue adapting to the effects of another long-term eruption.
Rangers share tips for viewing the Kīlauea “glow show”
More than 4,000 visitors a day flock to Hawai‘i Volcanoes National Park, smitten with the idea of witnessing a volcanic eruption in person. They all have one question in common: where’s the lava? Here’s what park rangers say:
Tip #1: The easiest and closest eruption viewing continues to be Kīlauea Volcano’s summit eruption from Halema‘uma‘u Crater. By day, a robust plume of gas, steam, and particulates rises from the depths of the crater; by night, the lava lake casts an ethereal and mesmerizing glow on the plume and the night sky.
Tip #2: Jaggar Museum is the closest visitors can get to the glowing lava lake deep within Halema‘uma‘u, and it’s the park’s most popular spot after 5:30 p.m. (6,670 people were counted there in December 2014!) If you can’t avoid peak hours, park staff might re-route overflow traffic to Kīlauea Overlook. Bring a flashlight and a jacket for the short walk to Jaggar Museum. Or consider observing the glow from a less-crowded location, like Keanakāko‘i, ‘Akanikōlea (Steam Vents), Waldron Ledge, or Kīlauea Iki Overlook.
Tip #3: Are you a night owl or an early riser? The best time to observe the hypnotic glow from the lava lake is before sunrise, or after 9 p.m., when most visitors have left. The park is open 24 hours a day.
Tip #4: Hō‘ihi (respect). Kīlauea Volcano, and Halema‘uma‘u in particular, are sacred to Hawaiians. This is where Pelehonuamea, the volcano goddess, makes her home. Can you feel her energy, hear her rumblings, feel her warm breath? The many manifestations of Pele remind us that we are in her home. Indeed, many Hawaiians come to honor Pelehonumea privately with ‘oli (chants), mele (song) and hula (dance).