Kīlauea Eruption Update, 4 Months In: April 20, 2021

As Kīlauea’s ongoing eruption reaches the four-month milestone, its output rate continues to gradually decline. Still, lava continues flowing into and filling a summit lava lake within Halemaʻumaʻu crater. According to the USGS Hawaiian Volcano Observatory, “the lava stream [into the lake] was covered in a thin, flexible crust and was moving at a very slow velocity.” Other than small changes in the lake entry, occasional small flows continue around the West Vent. Still no signs of any major change in the eruption apparent in monitoring signals, and the low-effusion phase continues. Latest on Kīlauea, Eruption Day 121, Week 17, and statistics through 4 months: -West Vent entry points remain submerged, and their pathways crusted over, though occasional increases in flow lead to overflows from the cones -- this week towards the crater wall, last week into the lake -Lava lake crested at 745 ft / 227 m deep during the past week (USGS). The lake filled 663 ft / 202 m during the first month, 55 ft / 16 m in the second month, 14 ft / 5 m in the third month, and 9 ft / 3 m in the past month. -Small, triple Deflation-Inflation event ongoing; correspondingly, lake surface lowers slightly to 741 ft / 226 m deep, and no ooze-up flows along crater walls during past week. -GPS across summit caldera measuring continuing extension, but at a slower rate over the past month. Seismic activity below background, mostly focused below summit and South Flank. -SO2 last week measured at 950 tonnes/day (USGS), within average range of the past 2 months. Maximum reported emissions of 50,000 t/d during the first month, 2,200 t/d in the second month, 1,100 t/d in the third month, and 1,200 t/d during the past month. -Total eruption area 44 hectares / 109 acres, active lake area down to 3 hectares / 8 acres -Lake volume 39 Million cubic meters / 10 Billion gallons -Unofficial estimated output over the past month of ~20 ft3/s / ~0.5 m3/s. First month ~400 ft3/s / ~10 m3/s, second month ~80 ft3/s / ~2 m3/s, third month ~40 ft3/s / ~1 m3/s. (Peak ~3200 ft3/s / ~90 m3/s on the second day; average over the whole eruption ~140 ft3/s / ~4 m3/s from calculations based on preliminary USGS data reports.) We review monitoring data, time-lapses and photos on Kīlauea's ongoing eruption available courtesy of the USGS Hawaiian Volcano Observatory, including a closer look at the small pulses of lava flows at the West Vent, and as usual, discuss live viewer questions. https://www.youtube.com/watch?v=e-bk6LJLyB4