Tuesday | October 17, 2017
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Volcano Watch: Kilauea Volcano’s summit eruption in Halema‘uma‘u Crater reaches 9th anniversary

Kilauea Volcano’s summit eruption in Halema‘uma‘u Crater began in March 2008.

Since that time, countless changes have occurred.

The crater enclosing the lava lake (called the Overlook crater) has enlarged through rockfalls, and explosions have thrown spatter around the crater and onto the rim of Halema‘uma‘u itself. The lava lake level has fluctuated, leading to several overflows of lava onto the Halema‘uma‘u Crater floor.

The past year has been a notable one for a simple reason: the lake now is frequently visible from public viewing areas. For most of the eruption, the lake has been too far beneath the crater rim to be seen, and only glow was visible from afar.

Lava levels rose sharply at the start of 2016, with the lake poised just out of view for the first half of the year.

During the second half of 2016, another rise finally brought the lake high enough that it has been commonly visible from Jaggar Overlook inside Hawaii Volcanoes National Park. The sight of the lake often is incredible, particularly at dawn and dusk, with clear views of the slowly shifting crustal plates and large gas bubbles bursting at spattering areas on the lake margin.

The lake today also is quite large compared with its modest beginning and compared with other lava lakes around the world. The surface area of the lake has slowly grown since 2008, and in 2016 it increased about 20 percent. The lake area now is about 39,000 square meters (10 acres).

Only a half dozen or so persistent lava lakes exist on Earth, including those at Erebus Volcano (Antarctica), Erta Ale Volcano (Ethiopia), Nyiragongo Volcano (Democratic Republic of the Congo) and Ambrym Volcano (Vanuatu).

Of these, only Nyiragongo has dimensions comparable to Halema‘uma‘u. Nyiragongo’s lake has been measured between 35,000 and 47,000 square meters (9 and 12 acres) throughout the past decade. The other lakes are all less than 4,000 square meters (1 acre). Halema‘uma‘u and Nyiragongo are, by a wide margin, the two largest lava lakes on Earth.

The high lava level is not only good for viewing opportunities, but it also facilitates better scientific studies of the lake. HVO scientists and their collaborators recently completed a number of studies that provide unprecedented insights into lava lake behavior.

For instance, we now know the lava lake in Halema‘uma‘u provides a “window” into the deeper magma system in some respects, but at the same time the lake has its own internal dynamics that are superimposed on these deeper signals.

Despite the lake providing a beautiful view and a unique opportunity for scientific study, it comes with one major drawback: vog.

All of that spattering releases large amounts of gas, which has to go somewhere. Most often, the gas plume is carried southwest by the trade winds, impacting air quality in the Ka‘u and Kona side of the island. When trade winds break down, other areas of the Big Island and even the entire state can be impacted by vog. More information about vog can be found at http://ivhhn.org/vog/

Could the lake rise even higher?

It’s possible a slight increase in magma reservoir pressure — possibly from an increase in magma supply from the mantle source — could push the lake level higher, leading to further overflows onto the Halema‘uma‘u Crater floor. If higher levels and overflows are sustained, they likely would lead to the development of a “perched” lava lake — that is, a lava lake contained within steep levees of solidified lava.

What is the overall outlook for the summit eruption?

Although the lake has slowly risen during the past year, and the summit slowly inflated in concert, the majority of monitoring indicators at Halema‘uma‘u have been relatively steady. Right now, there are no signs of the eruption slowing down.

Halema‘uma‘u Crater has a long history of lava lake activity, including decades of sustained lava lakes in the 1800s and early 1900s. This record demonstrates that the current eruption has the potential to last for many years.

As we approach a decade of continuous lava lake activity, it becomes easier to imagine the lava lake could be here for quite a while.

Volcano activity updates

Kilauea continues to erupt at its summit and East Rift Zone. This past week, the summit lava lake level varied between about 5 and 23 m (16 and 75 ft) below the vent rim. The 61g flow remained active, with lava entering the ocean near Kamokuna and small surface breakouts downslope of Pu‘u ‘O‘o on the pali and the coastal plain. The 61g flows do not pose an immediate threat to nearby communities.

Mauna Loa is not erupting. During the past week, small-magnitude earthquakes continued to occur beneath the volcano. GPS measurements continue to show deformation related to inflation of a magma reservoir beneath the summit and upper Southwest Rift Zone. No significant change in the summit fumarole temperature or gas output was noted.

One earthquake recently was reported felt on Hawaii Island. At 10:01 p.m. March 14, a magnitude-3.1 earthquake occurred 12 km (7.5 mi) south of Hawi at a depth of 24 km (15 mi).

Visit the HVO website (http://hvo.wr.usgs.gov) for past Volcano Watch articles, Kilauea daily eruption updates and other volcano status reports, current volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kilauea summary update; email questions to askHVO@usgs.gov.

Volcano Watch (http://hvo.wr.usgs.gov/volcanowatch/) is a weekly article and activity update written by U.S. Geological Survey`s Hawaiian Volcano Observatory scientists and colleagues.


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