Evening Kīlauea Eruption Update, December 26th

The eruption continues into this evening, though is less vigorous today than over the course of the previous week. Sulfur dioxide levels have dropped 50% today down from 35,000-40,000 tonnes per day on December 24th, to 16,000-20,000 tonnes per day last night. As the level of the lava inside Halema’uma’u rose, it eventually submerged the lower of the two primary eruptive vents. Lava erupting from the northern vent slowly ceased erupting and then began to flow back into the vent around 3am this morning. At roughly the same time, the western vent became briefly more active and formed three different rivers of lava draining into the lake from a 32 foot tall lava fountain, before slowing later in the morning. The level of the lava lake since the 3am episode this morning has not only stopped rising, the lava level has decreased by as much as seven feet as lava drains back into the system beneath the surface through inactive fissures. Along with the changes in eruptive activity that took place around 3am, ground tiltmeters picked up a trend change in ground deformation when the deflationary tilt that has been observed from eruption onset changed to an inflationary trend. The inflationary trend likely relates to the eruption stopping and reversing at the northern vent. According to USGS, the decreased effusion rate and slight inflation at the summit indicates that the western fissure cannot accommodate the volume of lava being erupted at the northern fissure. “The western vent might eventually become more vigorous, a new vent could open up in the same area, or the eruption could pause.” Said @USGSVolcanoes social media team, “Often we see a cycling of eruptions, with drainback and then eruption and then drainback once again -- like in the 1959 Kilauea Iki eruption” LERZ - There are no indications that magma supply to the rift zones has changed. USGS reports that the Middle East Rift Zone has been contracting while the summit inflates. No significant change in seismic activity on the rift zone. Images from USGS-HVO, annotated by Hawaii Tracker. Captions from USGS in order images appear. Image 1 - "A zoomed photo of the Halema‘uma‘u crater lava lake at Kīlauea Volcano’s summit. The northern fissure vent (upper center) is inactive and slow lava lake draining continues at the site. The “bathtub ring” of cooled lava is visible around the perimeter of the lava lake, and the several meters (yards) of lava level drop is also visible around the rafted island (center). USGS photo by N. Deligne." Image 2 - "An aerial photograph of Halema‘uma‘u crater at Kīlauea Volcano’s summit shows changes to the ongoing eruption. Around 2:40 a.m. HST the western fissure, which has been weakly active for several days, increased in eruptive vigor as all three vents started producing spatter and streams of lava. Shortly before 3:00 a.m. HST the northern vent, which had been the dominant eruptive vent, was drowned by the lava lake and shut down. SO2 emission rates, as measured this morning, have dropped significantly but are still elevated. This USGS photo was taken at approximately 9:30 a.m. HST on December 26 by M. Patrick." Image 3 - An aerial thermal image taken during a Hawaiian Volcano Observatory overflight this morning around 9:30 a.m. HST. The western fissure vents (upper left) remain active and continue to produce small lava streams that are feeding into the lava lake. The northern fissure has shut down, and field crews report that the lava lake is slowly draining at the northern fissure site (upper right). A cooled ledge of lava, like a ring on a bathtub, surrounds the perimeter of the lava lake as it slowly drains (cooler color surrounding the lava lake). This afternoon, the lake level was reported to have drained by up to several meters (yards). USGS thermal image by M. Patrick. Image 4 has no caption, but shows the western vent this morning. Image 5 - As of about 2:40 a.m. HST on December 26, 2020, activity at the west vent in Halema‘uma‘u crater wall at Kīlauea's summit has increased. This photo, taken at approximately 5:15 a.m. HST shows fountaining at the west vent, and lava pouring from the north end of the fissure into the growing lava lake. HVO field crews monitoring the activity overnight measured the west vent lava fountains as at least 10 m (32 ft) high. USGS photo H. Dietterich.