Dome Fountain Occurring Within Halema‘uma‘u Lava Lake
8 AM HST Thursday, Jan. 7, 2021: USGS Hawaiian Volcano Observatory
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
Dome fountains with an estimated height of 16 feet have been occurring in recent days near the west vent feeding the Halema‘uma‘u lava lake. This morning, lava is presumed flowing through crusted channels to the lake and also feeding a small photogenic dome fountain in front of the west vents probably from a submerged portion of the vent.
Lava activity remains confined to Halemaʻumaʻu with lava erupting from vents on the northwest side of the crater. Wednesday afternoon, the lava lake was 636 feet deep and perched 1-2 yards above its edge. On Wednesday afternoon, the lake had a volume greater than 35 million cubic yards. The most recent thermal map (Jan. 5) provided the perched lake dimensions as 830 by 570 yards for a total area of 70 acres — slightly smaller than on Dec. 30 when the pervious thermal map was made. SO2 emission rates were still elevated.
Sulfur dioxide emission rate measurements made on Jan. 3 were in the range 3,000-6,500 t/d since last Dec. 27 — the same range of values that was common for emissions from the pre-2018 lava lake.
Geodetic monitors indicate that the upper portion of the East Rift Zone (between the summit and Puʻu ʻŌʻō) contracted while the summit deflated at the onset of this eruption. There is no seismic or deformation data to indicate that additional magma is currently moving into either of Kīlauea’s rift zones.
The main island of cooler, solidified lava floating in the lava lake continued rotating counter-clockwise, in front of the west lava source filling the lake, while the 11 smaller islands moved a bit but remained in the east end of the lake; at 10:30 pm last night, the island stalled in rotation and movement.
The dimensions of the main island remained the same: about 820 feet in length, 440 feet in width, and about 7 acres in area based on the Jan. 5 thermal map. Measurements on Jan. 1 showed that the island’s edges were about 20 feet above the lake surface. Monday afternoon, the island was measured as 8-9 yards higher above the lake surface.