The latest lava-fountaining episode at the volcano was one of the most intense of the series and remarkable in several ways. Here’s the official observatory report:
„Episode 38 of the ongoing Halemaʻumaʻu eruption ended abruptly at 8:52 p.m. HST on December 6 after 12.1 hours of continuous lava fountaining.
The south vent stopped erupting at approximately 8:52 p.m. HST, marking the end of the episode. The dual north vents stopped erupting much earlier at approximately 11:50 a.m. Lava fountains reached heights of up to 1,000-1,200 ft (300-370 m) during episode 38. Fountains were down to about 400 feet (120 meters) high just before the abrupt end of the eruption. Lava fountaining lasted for 12.1 hours and produced an estimated 16 million cubic yards (12 million cubic meters) of lava. The combined average eruption rate was over 250 cubic yards per second (190 cubic meters per second) from the lava fountains.
Sustained lava fountains began erupting from two vents located within the north cone at 8:45 a.m. HST on December 6 after just over 5 hours of precursory lava overflows. The south vent then began fountaining at 8:49 a.m. By 9:15 a.m. a rare triple fountain event was underway with the two north vents and the south vent all erupting together at heights of about 500 feet (150 meters). By 9:40 a.m. the south vent fountain grew to about twice as high as the north vent fountains. The highest peak or instantaneous effusion rate of 1,300 cubic yards per second (1,000 cubic meters per second) occurred just before 10 a.m. when the south vent exploded. The enlarged south vent produced an inclined fountain over 1,000 feet (300 meters) tall that sprayed the south wall of Halemaʻumaʻu crater. Hot pumice and molten spatter from this fountain destroyed the HVO „V3“ streaming camera site.
Lava flows from this episode’s fountains covered 50-60% of the floor of Halemaʻumaʻu crater. Lava flows near the vents and on the floor of Halemaʻumaʻu within the southern part of Kaluapele (Kīlauea caldera) may continue to exhibit slow movement or incandescence as they cool and solidify over the coming days.
Volcanic gas emissions have greatly decreased with the end of the eruption. Earlier today the gas plume reached over 20,000 feet (6000 meters) above sea level. Tephra including Pele’s hair and fine ash carried in lower levels of the plume fell in the town of Pahala and other communities southwest of the vents. Satellite imagery showed the upper regions of the gas and ash cloud moved due east of the summit across lower Puna and well out to sea before turning south. Reticulite pieces up to the size of a baseball fell along Chain of Craters Road east of Kīlaueaʻs summit transported by the high eastern plume. The extremely high effusion rates early in the eruption provided the gas and heat that drove this enormous plume.
The Uēkahuna tiltmeter (UWD) recorded about 33.1 microradians of deflationary tilt during this episode. The end of the eruption was coincident with a rapid change from deflation to inflation at the summit and a decrease in seismic tremor intensity.“
Source: HVO / USGS
