Ka‘ū News Briefs Thursday, May 10, 2018

Thomas Jaggar examines a 12 ton block ejected from Halemaʻumaʻu Crater onto the floor of Kīlauea Caldera in 1924. Scientist warn that such an explosive event, driven by steam, could happen as soon as Friday as the summit lake drops to a level where the lava could mix with groundwater. HVO photo

HAWAIʻI VOLCANOES NATIONAL PARK SHUTS DOWN AT 9 P.M. TONIGHT until further notice. The park will close all areas but the Kahuku Unit off Hwy 11 near Ocean View.
     Park officials said they are concerned about the possibility of steam and rock explosions at Halemaʻumaʻu Crater that could be caused by lava mixing with groundwater. The likelihood becomes greater as the lava lake lowers toward the level of groundwater. The lava lake has been sinking for more than a week, as lava flows underground, away from the summit crater into lower Puna. Lava in the summit crater could reach groundwater as early as tomorrow, said scientists from Hawaiian Volcano Observatory.
     A similar event happened in 1924, with blocks as heavy as 14 tons thrown from the crater, with explosions lasting for two and a half weeks. Halemaʻumaʻu more than doubled in size. The lava lake disappeared for many decades and only rose back up to its recent glory in 2009.

A dust cloud during the collapse of Halemaʻumaʻu crater floor in 1924. HVO photo

     The National Park closure includes Kīlauea Military Camp and Volcano House accommodations, bars,
restaurants, and other concessions; Volcano Art Center Gallery; the KMC bowling alley and theatre; and Hawaiian Volcanoes National Park Post Office. Post office delivery will be switched to Volcano Village.
     Park officials said the steam explosions could be life-threatening, throwing rocks as large as 6 feet in diameter up to 0.6 miles away.
     Also expected is ashfall - either from rocks falling into the crater, creating ash explosions, like those rising as high as 6,000 feet on Wednesday, or from steam and rock explosions themselves.
     Tina Neal, USGS HVO Scientist-in-Charge, told press conference attendees today that ash is "pulverized rock" and "not toxic, but an irritant." See article, below, about dealing with ashfall.
     When asked how much longer the volcanic events from lower Puna to Volcano would last, Neal responded they have historical precedence, not only in 1924 but also in 1955 and 1960, and may last between 36 and 88 days. When asked about "dramatic fountaining," such as seen in the 1984 eruption at Puʻu ʻŌʻō, Neal said such a spectacle could happen if fresh, gassier lava arrives at fissure points.
     Wes Thelen, of USGS Science Center, stated the magma has moved downrift, at least as far as Noni Farms Road in lower Puna; scientists do not know how much farther it will travel.
     As of noon today, there was no volcanic activity on the East Rift Zone and Leilani Estates residents were allowed back in their homes to gather belongings. Civil Defense reported that all of the pentane gas containers were removed from the Puna Geothermal plant, which remains closed, about a third of a mile from the nearest fissures that have opened with lava. Some residents near the geothermal plant have left their homes, saying they fear the lava will reach the plant and cause explosions.


THE POSSIBILITY OF ASHFALL REACHING KAʻŪ from Halemaʻumaʻu has prompted preparation by members of the community. A guide available at Nāʻālehu library and online explains "the potential health effects of volcanic ash" and gives details on "how to protect yourself and your family in the event of a volcanic ashfall." Prepared by the International Volcanic Health Hazard Network, Cities and Volcanoes Commission, GNS Science, and the United States Geological Survey, it is designed "to promote the safety of those who experience volcanic ashfall."
     Some simple steps to be taken during ashfall include limiting time outdoors, closing windows and doors, and wearing protective clothing and face coverings. Various masks from those blocking only dust, to those blocking chemicals, have been going on sale at stores in Kaʻū.
     The pamphlet can be viewed and downloaded.

SO2 made air unhealthy before dawn this morning, but improved over the day in Pāhala, though readings were unavailable this afternoon and evening. Graph from state Department of Health

AIR QUALITY VARIED IN KA‘Ū TODAY, with some reports of ashfall in Pāhala and Waiʻōhinu. In both Pāhala and Ocean View, the SO2 reached levels unhealthy for sensitive groups during the period before dawn, but cleaned up for the morning. The readings were unavailable in the afternoon and evening in Pāhala but showed healthy readings in Ocean View.
Ocean View showed a moderate reading for particulates this evening, with no data for Pāhala.

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A WATER ADVISORY WAS ISSUED BY HAWAIʻI VOLCANOESNATIONAL PARK today. Chlorine levels in the park have lowered. The cause “is suspected to be related to recent elevated seismic activity at the Kīlaueasummit. Staff members are flushing the system and raising chlorine levels back to normal. The park recommends not drinking the water until "the work is complete and we update this message,” states the Park website.