Morning Eruption Update December 26: Lava Fountaining Switches to Western Vent

The eruption continues this morning in Halema‘uma‘u crater at Kīlauea's summit. The big change overnight happened around 2:40 a.m. when USGS crews noted that activity at the northern vent is down significantly and fountaining started back up at the western vent. Fountaining as high as 32 feet has been observed by USGS. It appears the northern vent got blocked by the lava lake and the pressure caused the western vent to start up again. The lava lake is now 583 feet deep, up 5 feet over the past 24 hrs. According to USGS this morning, the western vent is 111 feet above the lava lake at the moment. That means there is plenty of time for the western vent to fountain before it will get blocked by the lava lake. More information and updates to come. Latest from USGS Saturday Morning: Activity Summary: Lava activity is confined to Halemaʻumaʻu from two vents on the north and northwest sides of the crater. As of 2 pm yesterday, the crater lake was still 176 m (577 ft) deep and the lake level appeared to be 2 m (6 ft) lower leaving a narrow black ledge around the north edge. Early this morning, the west vent reactivated while the north vent quieted and started to drain the lake. Reduced SO2 emissions were measured last night. Summit Observations: Preliminary analysis of sulfur dioxide emission rates measured last night suggest that the rates have dropped to 16,000-20,000 tonnes/day. Summit tiltmeters continued to record slowing deflationary tilt until just before 3 am this morning (Dec. 26) when it switched to inflationary tilt. Seismicity remained elevated but stable, with a few minor earthquakes and tremor fluctuations related to the vigor of fissure fountaining. Halemaʻumaʻu lava lake observations: The north vent continued erupting lava into a lake within Halemaʻumaʻu crater. The west vent was incandescent until about 2:40 am this morning (nearly coincident with the switch from deflationary to inflationary summit tilt) when it became vigorously active with up to 3 narrow lava streams into the lake . After 3 am the north vent quieted and started to slowly drain lava from the lake. The lava lake within Halemaʻumaʻu crater remained about 176 m (577 ft) deep and about 415 m (1,360 ft) below the Halemaʻumaʻu rim as of yesterday afternoon (Dec. 25th). The lava lake volume remained about 21 million cubic meters (27 million cubic yards or 4.8 billion gallons). USGS field crews are currently making measurements to confirm whether the lake surface continues to drop. An island of cooler, solidified lava floating in the lava lake, which has been drifting slowly northeastward in the lake, has apparently grounded itself near the north vent. It is still about 260 m (850 ft) in length and 115 m (375 ft) in width based on the Dec. 23rd thermal map (https://www.usgs.gov/maps/december-23-2020-k-lauea-summit-eruption-thermal-map). At about 6 am this morning (Dec. 26), the island started to slowly drift to the southeast. Webcam views of the lava lake can be found here: https://volcanoes.usgs.gov/volcanoes/kilauea/multimedia_webcams.html Image 1 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. Image 2 The eruption continues in Halema‘uma‘u crater at Kīlauea's summit. HVO field crews observing the activity overnight noted that at approximately 2:40 a.m. HST December 26, 2020, activity at the west vent in the wall of Halema‘uma‘u rejuvenated: the west vent has become more active than the northern vent. Since the start of the eruption on December 20 at 9:30 p.m. HST, the northern vent has been dominant and erupting more vigorously than the weaker western vent. Over the past two days, the northern vent has slowly been drowned by the rising lava lake, and this photo (taken at about 5:15 a.m. HST on Dec. 26) shows that the west vent is now erupting more vigorously. At 3:30 a.m. HST today (Dec. 26), HVO field crews measured the rising lava lake as 178 m (583 ft) deep. USGS photo by H. Dietterich. Image 3 (map) Lava lake level measurements collected during a field visit of Kīlauea Volcano's summit around 2:15 p.m. HST on December 25, 2020, were used to create a preliminary lava lake depth map. When compared to pre-eruption topographic models, it shows that the bottom of Halema'uma'u crater has been filled by almost 176 m (578 ft) of lava. Map by H. Dietterich. Image 4 Webcam image from this morning of Halemaʻumaʻu, lava lake, and down-dropped block [KWcam] From the west rim of the new summit collapse features