Following decades of gentle, predictable lava eruptions Hawaii’s Kilauea volcano has exploded ash to 30,000 feet. Scientists had evacuated the Hawaiian volcano observatory so no injuries have been reported. People living in the nearby town of Volcano have been warned by Hawaii’s civil defense to stay indoors to avoid falling ash. This turn to explosive eruptions was successfully forecast by USGS volcanologists based on falling lava levels in the central caldera. As lava levels dropped, rockfalls increased as expected. When lava levels dropped to the level of the water table, explosions of steam mixed with pulverized rock began. This morning’s eruption was the most explosive event of this eruption cycle and the highest eruption of ash at Kilauea documented by modern technology.
The US Geological Survey reports that the volcano has quieted down after this morning’s explosive eruption, but more violent outbursts are possible as the eruption continues. Because Kilauea stores enormous amounts of magma underground in both the rift zones and magma chamber(s) below the volcano, there is no good way to predict how long this eruptive sequence of events will progress or how severe it will get. Apparently the lava erupted to date has been stored since an eruption in the 1950’s and that eruption involved material that may have been stored for hundreds of years. Older lava stored near the surface is cooler, less fluid and less gassy. That’s why the lava flows have moved slowly and the eruption has been relatively mild up to the ash eruptions of the last several days. The eruption could become more vigorous if fresher magma moves into Kilauea and the east rift zone.
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HILO >> A U.S. Geological Survey geologist described the pre-dawn explosive eruption at the summit of Kilauea as “short-lived” and not having a “widespread impact.”
Scientist Michelle Coombs said at a morning news conference at Hawaii County Civil Defense headquarters in Hilo that the event, which sent a cloud of ash and smoke up to 30,000 feet high, was “consistent with what we were thinking might happen.” She said the ashfall was “localized” around the summit.
She said it was a “real dynamic situation up there” on the summit, and that similar explosive events are still possible.
Coombs called the 4:17 a.m. eruption as the “the biggest so far” at the summit and that it may have relieved pressure temporarily in the caldera at Halemaumau Crater.
Although she could not say with certainty, Coombs said that the event appeared consistent with the dropping lava lake hitting groundwater, as geologists have been expecting.
Volcano cafe has an excellent background story on the 1955 eruption.
www.volcanocafe.org/…
The USGS has illustrated why the eruption has become explosive.
The pattern of earthquakes over the past 24 hours shows that magma continues to move underground in the east rift system. If magma continues to move east-northeastward from Kilauea’s caldera into the shoreward end of the east rift, the lava level in the caldera is likely to continue to drop and explosive activity is likely to continue.
The fissure eruption continues in lower Puna on the east rift zone. This video by Honolulu Civil Beat was live on Youtube Friday morning east coast time. The live stream is now over.