Ka`u News Briefs Saturday, March 18, 2017

     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 Halemaʻumaʻu itself. The lava-lake level has fluctuated, leading to several overflows of lava onto the Halemaʻumaʻu Crater floor.

Sunset view of the Kīlauea summit lava lake showing an active  area of spattering at the right margin. Jagged openings between  cooler crustal plates reveal molten lava. HVO is faintly visible on  the Kīlauea Caldera rim at upper left. USGS photo

     The past year has been a notable one for a simple reason: the lake is now 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 that year. 

     During the second half 2016, another rise finally brought the lake high enough that it has been commonly visible from Jaggar Overlook inside Hawai'i Volcanoes National Park. The sight of the lake is often 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 is also quite large compared with its modest beginning and compared with other lava lakes around the world. The surface area of the lake has been slowly growing since 2008 and in 2016 it increased about 20%. 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).

The lava lake in Hawai`i Volcanoes National Park has risen to high levels for excellent viewing. USGS photo

     Of these, only Nyiragongo has dimensions comparable to Halemaʻumaʻu. Nyiragongo's lake has been measured between 35,000 and 47,000 square meters (9-12 acres) over the past decade. The other lakes are all under 4000 square meters (1 acre). Halemaʻumaʻu 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 have recently completed a number of studies that provide unprecedented insights into lava lake behavior.
     For instance, we now know that the lava lake in Halemaʻumaʻu 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, the lake comes with one major drawback: vog. All of that spattering in the lake releases large amounts of gas, which has to go somewhere. Most often, the gas plume is carried southwest in the trade winds, impacting air quality in the Ka`u district and Kona side of the island. When trade winds break down, other areas of the Island of Hawai`i and even the entire state can be impacted by vog. More information on vog can be found at:http://ivhhn.org/vog/

Telephoto view of Halemaʻumaʻu from Hawai‘i Volcanoes National  Park’s Jaggar Overlook on October 15, 2016.  NPS photo by J. Wei

     Could the lake rise even higher? It's possible that 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 Halemaʻumaʻu Crater floor. If higher levels and overflows are sustained, they would likely 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 over the past year, and the summit has slowly inflated in concert, the majority of monitoring indicators at Halemaʻumaʻu have been relatively steady. Right now, there are no signs of the eruption slowing down.
     Halemaʻumaʻu 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 that the lava lake could be here for quite a while.

Volcano Activity Updates: Kīlauea 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 (16-75 ft) below the vent rim. The 61g flow was still active, with lava entering the ocean near Kamokuna and small surface breakouts downslope of Puʻu ʻŌʻō 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 this past week.
     One earthquake was reported felt on the Island of Hawai'i during the past week. On Tuesday, March 14 at 10:01 p.m. HST, 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, Kīlauea daily eruption updates and other volcano status reports, current volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea summary update; email questions to askHVO@usgs.gov.

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RENTAL HOUSING ASSISTANCE FOR POOR FAMILIES would be radically reduced under President Donald Trump's proposed 2018 federal budget. The assistance, which subsidizes rents to landlords depending on family incomes, is a nationwide program with federal grant money locally managed by Hawai`i County. It is often referred to in Hawai`i as "County Housing" and helps many families in Ka`u.
      The National Low Income Housing Coalition recently reported a shortage of seven million affordable homes for extremely low-income households throughout the country. Extremely low income people can pay 70 percent of their income for rent and utilities. "Every household that loses its rental voucher is at risk of becoming homeless," said David Reiss, director of academic programs at the Center for Urban Business Entrepreneurship. Writing in The Hill, he stated that years ago the country's Declaration of National Housing Policy set fort the "goal of a decent home and a suitable living environment for every American family." The program, which helps 4.5 million families nationwide, is not only those without housing but also for "the general welfare and security of the nation," says the Declaration of National Housing Policy.

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RESPONDING TO HAWAI`I FEDERAL JUDGE Derrick Kahala Watson's stop to Pres. Donald Trump's recent travel ban of people from six Muslim-majority countries, a Hashtag #BoycottHawaii was born.
    Trump supporters urge people to take vacations elsewhere and others celebrate Trump supporters staying away, writing:
    "When you realize #BoycottHawaii is something Hawaiians were trying to do since the beginning.." and "Anyone who wants to #BoycottHawaii can slide those plane tickets right over here. Hotel reservations too."
       Others: "Got to love the stupidity of the #BoycottHawaii just means more room on the beach for me when I go" and "Fewer narrow-minded bigots littering our beaches and mocking our traditions."

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Make Hū Kukui, Wed, Mar 22, 10 a.m. – 12 p.m., Kīlauea Visitor Center lānai in Hawai`i Volcanoes National Park. Help revive the practice of making and playing the traditional Hawaiian top. Free; Park entrance fees apply.

Coffee Talk, Fri, Mar 24, 9:30 – 11 a.m., Kahuku Unit of Hawai`i Volcanoes National Park. A monthly series of talks on various subjects. nps.gov/havo or 985-6011

Exploring Tunnel Books, Sat, Mar 25, 9 a.m. – 12 p.m., Volcano Art Center. Participants take a trip down the rabbit hole with Charlene Asato. $35/$32 VAC members plus $10 material fee. 967-8222