Categorized | Sci-Tech

Volcano Watch: Activity update for week of Feb. 20

(Activity updates are written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

Kilauea Volcano continues to be active.

A vent in Halemaumau Crater is emitting elevated amounts of sulfur dioxide gas and producing small amounts of ash. Resulting high concentrations of sulfur dioxide in downwind air have closed the south part of Kilauea caldera and produced occasional air quality alerts in more distant areas, such as Pahala and communities adjacent to Hawaii Volcanoes National Park, during kona wind periods. Using a thermal camera, a small, puffing cone has been visible about 100 yards below the vent rim.  

Puu Oo also continues to produce significant amounts of sulfur dioxide. Trade winds tend to pool these emissions along the West Hawaii coast, while Kona winds blow these emissions into communities to the north, such as Mountain View, Volcano, and Hilo.
A pair of deflation/inflation (DI) events that began Sunday, Feb. 22 disrupted the supply of lava erupting from the Thanksgiving Eve Breakout (TEB) vent at the eastern base of Puu Oo.

The flow of lava through the lava tube was cut off, and the ocean entries at Waikupanaha and Poupou both died. The east rift zone eruption resumed on the 25th, and lava reached the ocean again late on Wednesday, Feb. 25, at Waikupanaha. The Poupou entry had not restarted as of this writing on Thursday, Feb. 26, but coastal plain breakouts we active nearby.

Be aware that active and recently inactive lava deltas can collapse at any time, potentially generating large explosions. This may be especially true during times of rapidly changing lava supply conditions. The Waikupanaha delta has collapsed several times in the past year, with four of the collapses resulting in rock blasts. These blasts have tossed television-sized rocks up onto the sea-cliff and have thrown fist-sized rocks more than 275 yards inland.

Mauna Loa is not erupting. Three earthquakes were located beneath the summit this past week. Continuing extension between locations spanning the summit indicates slow inflation of the volcano, combined with slow eastward slippage of its east flank.

One earthquake beneath Hawaii Island was reported felt within the past week. A magnitude-3.4 earthquake occurred at 11:25 p.m., Saturday, Feb. 21 and was located 5 miles west-northwest of Kaena Point at a depth of 6.5 miles.
Visit the Web site ( for daily KÄ«lauea eruption updates, a summary of volcanic events over the past year, and nearly real-time Hawaii earthquake information. KÄ«lauea daily update summaries are also available by phone at 967-8862. Questions can be emailed to

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