Lava Lake Continues to Slowly Rise
8 AM HST Thursday, Dec. 31, 2020: USGS Hawaiian Volcano Observatory
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
The lava lake within Halemaʻumaʻu crater continued to enlarge slowly in the past few days. Lava activity remains confined to the crater with lava erupting from vents on the northwest side. Over the past 24 hours, the lava lake depth measurements have ranged from 593 to 608 feet deep with a narrow black ledge around it. Reduced, but still elevated, SO2 emissions were measured Dec. 30.
Measurements of the lake taken ate last night and early this morning were made in extremely windy conditions and may not be as accurate as earlier measurements made in calmer conditions. The most recent thermal map (Dec. 30) provided the lake dimensions as 875 by 580 yards for a total area of 82 acres. The narrow ledge around the lake was about 1-2 yards above the active lake surface.
Preliminary analysis of sulfur dioxide emission rates measured Wednesday show that the rates are about 3,800 tonnes/day– about the same as on Dec. 28 and slightly lower than the Dec. 27 rate of 5,500 t/d, but still elevated; all three of the most recent emission rates were in the range of values common for the pre-2018 lava lake. Seismicity remained elevated but stable, with steady elevated tremor and a few minor earthquakes.
Over the past day, the main island of cooler, solidified lava floating in the lava lake continued to drift slowly to the west while the other 10 or so small islands stayed put around the east end of the lake. The main island measured about 820 feet in length, 440 feet in width, and about 7 acres in area based on the Dec. 30 thermal map. Measurements yesterday evening (Dec. 30) show that the island surface was about 20-26 feet above the lake surface.