Categorized | Sci-Tech

HVO daily update for Nov. 23

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This Quicktime movie (at x2 speed) shows a small explosive event in the Halemaumau vent at 9:20 a.m. Saturday, Nov. 21. The explosion was immediately preceded by a portion of the vent rim collapsing into the vent cavity. The brown plume rises rapidly from the vent. In the video shown here, it is possible to see some particles impact the crater wall — look for several small white puffs to appear on the crater wall just ahead of the rising brown plume (about 7-9 seconds into the video clip). No ejecta was found at the Halemaumau Overlook, indicating that few, if any particles, reached the crater rim.

(This update was provided by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

A DI event started early Monday. At the summit, a circulating, bubbling, spattering, rising, and falling lava pond surface was visible in a hole in the vent cavity floor deep beneath Halemaumau Crater floor.

Sulfur dioxide emission rates from the Halemaumau and east rift zone vents remain elevated. Lava flows are active on the coastal plain; lava flows through tubes to the coast and is entering the ocean at two locations west of Kalapana.

Overnight, the lava pond, visible in a hole in the floor of a pit in the Halemaumau Crater floor, continued to circulate, bubble, and spatter; several times, the pond level rose to cover the floor, then drained back into the hole.

At about 4 a.m. Monday, part of the pit floor fell in enlarging the hole and revealing more of the lava pond surface. Glow is visible from the Jaggar Museum Overlook. The slightly wispy, off-white plume moves to the southwest.

The most recent sulfur dioxide emission rate measurement was 800 tonnes/day on Nov. 20, still elevated above the 2003-2007 average of 140 tonnes/day. Very small amounts of mostly ash-sized tephra continued to drop out of the plume near the vent.

The summit tiltmeter network recorded the start of DI deflation at about 2:40 am Monday. The GPS network, which is less sensitive than the tiltmeter network, recorded contraction, starting at the beginning of November, extension after Nov. 12, and is now again recording contraction.

Seismic tremor levels remained at low values with a brief decrease during each rise in lava level deep in the Halemaumau Overlook vent pit.

Seven earthquakes were strong enough to be located – three beneath the area just north of the summit caldera, three beneath an area west of the lower southwest rift zone, and one on south flank faults.

Magma continued to degas through Puu Oo crater before erupting from the TEB vent, located 2 miles to the east. The most recent sulfur dioxide emission rate measurement was 1,300 tonnes/day on Nov. 20, below the 2003-2007 average of 1,700 tonnes/day.

Lava flows through two tube branches to the coast, across state-owned and privately-owned land, and was entering the ocean at three general locations at Waikupanaha, west Waikupanaha 2,300 feet to the west, and areas in-between.

Overnight, UHH geologists and CD officials reported scattered active surface flows on the coastal plain, active ocean entries in three broad locations, and small surface flows active at the top and the base of the pali. GOES-WEST imagery showed thermal anomalies on the coastal plain suggesting continuing surface flow activity through dawn.

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