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A New Eruption In Halemaʻumaʻu - USGS Volcano Watch

Kīlauea volcano is erupting again. Wednesday afternoon, lava returned to Kīlauea's summit within Hawaiʻi Volcanoes National Park after a 4-month hiatus. A new line of fissures sliced through the solidified crust of the 2020–21 lava lake in Halemaʻumaʻu at 3:21 p.m. HST. Like the prior eruption that began in December 2020, this new activity is confined entirely within Halemaʻumaʻu. The new lava is continuing to fill the crater that collapsed in 2018 and is creating a new lava lake on top of the older one. Similar lava lakes frequently formed after collapse events in Halemaʻumaʻu in the 1800s. This pattern of summit collapse and subsequent lava lake filling is one that Kīlauea has exhibited in the past. Both the December 2020 eruption and current eruption were immediately preceded by about an hour of elevated seismicity beneath Halemaʻumaʻu. However, increased earthquake activity in the summit or upper East Rift Zone—as well as intrusions of magma beneath the summit region—provided clues of increased eruption potential prior to the eruptions. Following the intrusion of magma into Kīlauea’s south caldera and Southwest Rift Zone in late-August 2021, earthquake counts dropped to very low levels. Earthquake activity slightly increased on September 24, breaking the one-month-long seismically quiet period. A swarm of earthquakes began in the upper East Rift Zone beneath Pauahi Crater just before midnight on September 28 and alerted HVO seismologists to an increase in activity. Overnight, smaller earthquakes were recorded closer to the summit followed by a smaller swarm near Puhimau Crater on Chain of Craters road within Hawai‘i Volcanoes National Park. After a relatively quite morning on September 29, earthquake activity abruptly increased beneath Kīlauea’s summit around 2:00 p.m. About 30 minutes later the intensity, frequencies, and shallowness of earthquakes coupled with rapid changes in ground deformation patterns, indicated magma was moving upward beneath Halemaʻumaʻu. These changes prompted the USGS Hawaiian Volcano Observatory (HVO) to issue a Volcanic Activity Notice (VAN) and Volcano Observatory Notice for Aviation (VONA), elevating Kīlauea’s Volcano Alert Level and Aviation Color Code to WATCH/ORANGE at 3:09 p.m. The change in status indicated that an eruption could be imminent and fissures opened in the floor of Halemaʻumaʻu less than 20 minutes later. A second VAN/VONA was released, raising Kīlauea’s Volcano Alert Level and Aviation Color Code to WARNING/RED to notify the public and emergency managers that a new Kīlauea summit eruption had begun. Summit tiltmeters began to record a higher rate of inflationary tilt during the 40 minutes preceding the start of the eruption; a total of 11 microradians at the nearest instrument. After the onset of the eruption, the tilt changed to a steady deflationary trend that is continuing. Immediately before lava erupted, uplift of the older, solidified crust was seen in a few webcam image frames in the area where the fissures opened. The initial fissure cut across the middle of the Halemaʻumaʻu crater floor and was followed about an hour later (around 4:40 p.m.) by a fissure with several vents on the western wall of Halemaʻumaʻu. Multiple active vents continue to feed the growing lava lake that has risen approximately 20 m (65 ft) since the eruption started. The tallest lava fountain, near the southern end of the lava lake, has been measured at sustained heights of approximately 20–25 m (65–82 ft) throughout the night and into the morning of September 30th. A preliminary calculation of the average eruption rate so far was approximately 120 cubic meters (4,238 cubic ft) per second resulting in a total erupted volume of roughly 10 million cubic meters (350 million cubic ft). These high eruption rates are accompanied by huge releases of volcanic gases—especially sulfur dioxide (SO2)—which is one of the primary hazards related to summit eruptions. Initial rates of SO2 emissions were measured at about 85,000 tonnes per day just after the start of the eruption. The opening phases of eruptions can be unpredictable before the eruptive vents stabilize and HVO staff continue to monitor the ongoing eruption for any future changes. And while it’s not possible to predict exactly how long the current eruption may last, we expect that more summit and upper rift zone eruptions are likely in the coming years as Kīlauea continues to re-pressurize and re-establish magma pathways after the 2018 eruption. --- Volcano Watch is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates. --- Images and caption from USGS: Image 1: "Telephoto aerial image of eruption in Halemaʻumaʻu at Kīlauea Volcano's summit taken during an overflight at approximately 7:30 a.m. HST on September 30, 2021. A series of fountains in the central portion of the lava lake are visible, as well as the prominent vent in the west wall of Halemaʻumaʻu. The island, which formed during the early phase of the December 2020-May 2021 eruption within Halemaʻumaʻu, remains above the new lava lake surface and is visible in the center of the photo. USGS image by K. Mulliken. " Image 2 (map): A helicopter overflight on September 30, 2021, at approximately 7:30 a.m. HST allowed for aerial visual and thermal imagery to be collected of Halema‘uma‘u crater at the summit of Kīlauea. This thermal map shows a closer view of the new lava lake within Halema‘uma‘u. The scale of the thermal map ranges from blue to red, with blue colors indicative of cooler temperatures and red colors indicative of warmer temperatures. The dimensions of the new lava lake are 980 m (1070 yd) E-W axis and 710 m (780 yd) in N-S axis. The estimated area of the lake is about 52 hectares (127 acres). USGS map by M. Patrick.

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Episode 24

Episode 24

Episode 24 of the ongoing Halemaʻumaʻu eruption began at 8:55 PM HST on June 4 and is currently fountaining from the north vent. Episode 24 was preceded by sporadic spatter, gas pistoning, and hydrogen flames that began on the morning of June 3. At approximately 8:55 PM HST, episode 24 began with low dome fountaining accompanied by lava flows onto the crater floor. Small sustained lava fountains, less than about 100 feet (30 meters) high, began erupting from the north vent around 9:15 PM. Activity increased again around 10:10 PM, when fountain heights increased to 325 feet (100 meters) and by 10:40 reached over 980 feet (300 meters). Additionally, the fountain generated a plume that reached 16,500 feet (5,000 meters) above ground level by 10:50 PM and is increasing. At a tiltmeter near Uēkahuna (UWD), inflationary tilt reached just over 14 microradians since the end of the last episode; slightly more than the amount of deflationary tilt in episode 23. Seismic tremor began increasing and tilt at UWD switched from inflation to deflation at about 9:00 PM HST, close in time to the beginning of low fountaining. Most episodes of Halemaʻumaʻu lava fountaining since December 23, 2024, have continued for around a day or less and have been separated by pauses in eruptive activity lasting generally at least several days.

Ryan Finlay · 5d

Episode 18 Fountains Have Begun

Episode 18 Fountains Have Begun

Episode 18 high fountains have started!

Ryan Finlay · 2 months ago

Episode 17 Has Started

Episode 17 Has Started

Episode 17 of the ongoing Halemaʻumaʻu eruption began at 10:15 p.m. HST on April 7, 2025 with the start of lava overflowing from the south vent. Low spatter fountains from the south vent have been increasing from initial heights of 15-30 feet to 30-60 feet by 3:00 am HST on April 8. Tremor continues to gradually increase as well and is accompanied by slow deflation of the summit. - USGS Volcanoes

Ryan Finlay · 2 months ago

Episode 16 Has Ended

Episode 16 Has Ended

Episode 16 of the ongoing Halemaʻumaʻu eruption ended at 12:03 p.m. HST on April 2 when high fountaining at the south vent stopped. Fountains from the south vent sustained heights of 600-700 feet (180-210 meters) for over 23 hours, then dropped to less than 300 feet (90 meters) at 9:50 a.m. HST this morning, April 2. Overall, episode 16 lasted just over 37 hours with the last 25 hours and 39 minutes consisting of fountains from the south vent. During episode 16, lava flows covered over 50% of the floor of Halemaʻumaʻu within the southern part of Kaluapele (Kīlauea caldera). Weak winds also resulted in deposition of Pele's hair and tephra in closed areas of Hawai'i Volcanoes National Park and on Highway 11 between mile marker 35 and 37 on April 1. Additional details about the eruption were posted earlier in the March 31 Status Report and the April 1 Status Report and the April 1 Daily Update for Kīlauea along with the April 2 Daily Update for Kīlauea. The UWD tiltmeter recorded just over 14 microradians of deflation during episode 16, with 11 microradians lost on the SDH tiltmeter. Deflation rate was constant throughout the first part of the eruption reflecting the stable nature of activity from the south and north vents. The deflation rate slowed slightly after the north vent shut down April 1 at 9:22 p.m. HST. The end of the eruption was coincident with a rapid change in tilt from deflation to inflation at the summit and a decrease in seismic tremor intensity when the fountains ceased at 12:03 p.m. HST. Each episode of Halemaʻumaʻu lava fountaining since December 23, 2024, has continued for at least 13 hours, and up to 8 days, and episodes have been separated by pauses in eruptive activity lasting less than 24 hours to 12 days. Timeline of eruption episodes since December 23, 2024: https://www.usgs.gov/volcanoes/kilauea/science/eruption-information Two Kīlauea summit livestream videos are available here: Kīlauea Volcano, Hawaii (West Halemaʻumaʻu crater) v1cam and Kīlauea Volcano, Hawaii (East Halemaʻumaʻu crater)v2cam No changes have been detected in the East Rift Zone or Southwest Rift Zone. HVO continues to closely monitor Kīlauea and will issue an eruption update tomorrow morning unless there are significant changes before then. Kīlauea Volcano Alert Level/Aviation Color Code remain at WATCH/ORANGE. All current and recent activity is within Hawaiʻi Volcanoes National Park. Via USGS Volcanoes

Ryan Finlay · 2 months ago

Episode 16 High Fountains Have Started

Episode 16 High Fountains Have Started

The high fountaining stage of episode 16 has begun just now! “High fountaining began from the south vent at 10:24 am HST on April 1. The change was preceded by about 5 minutes of steadily increasing vigor. South vent fountains are currently about 200 feet (70 meters) high. No change at north vent.”

Ryan Finlay · 2 months ago

Episode 15 might be starting very soon!

Episode 15 might be starting very soon!

Update: the cycles are continuing with gaps of about 4 minutes. I started documenting these not thinking there would be this many cycles before the main fountaining started on this episode 😂. I'm going to head to bed so I won't be filling any more of the data in tonight. Have a good night everyone and enjoy the show. Episode 15 might be starting very soon! The lake was just visible with a good bit of fountaining, and now has dropped down. This cycle will keep repeating until the more vigorous fountains are continuous and much higher. When will the large fountains arrive? We shall see! North Vent Fountain Activity: 1st: Start 9:26 AM - Stop 9:32 AM - Gap to Next 23 minutes 2nd: Start 9:55 AM - Stop 10:01 AM - Gap to Next 10 minutes 3rd: Start 10:11 AM - Stop 10:20 AM - Gap to Next 9 minutes 4th: Start 10:29 AM - Stop 10:39 AM - Gap to Next 9 minutes 5th: Start 10:48 AM - Stop 10:58 AM - Gap to Next 9 minutes 6th: Start 11:07 AM - Stop 11:18 AM - Gap to Next 8 minutes 7th: Start 11:26 AM - Stop 11:37 AM - Gap to Next 7 minutes 8th: Start 11:44 AM - Stop 11:56 AM - Gap to Next 7 minutes 9th: Start 12:03 PM - Stop 12:19 PM - Gap to Next 6 minutes 10th: Start 12:25 PM - Stop 12:41 PM - Gap to Next 6 minutes 11th: Start 12:47 PM - Stop 1:03 PM - Gap to Next 5 minutes 12th: Start 1:08 PM - Stop 1:24 PM - Gap to Next 4 minutes 13th: Start 1:28 PM - Stop 1:41 PM - Gap to Next 5 minutes 14th: Start 1:46 PM - Stop 1:58 PM - Gap to Next 2 minutes 15th: Start 2:00 PM - Stop 2:15 PM - Gap to Next 4 minutes 16th: Start 2:19 PM - Stop 2:32 PM - Gap to Next 4 minutes 17th: Start 2:36 PM - Stop 2:48 PM - Gap to Next 3 minutes 18th: Start 2:51 PM - Stop 3:03 PM - Gap to Next 3 minutes 19th: Start 3:06 PM - 3:18 PM - Gap to Next 3 minutes 20th: Start 3:21 PM - 3:33 PM - Gap to Next 4 minutes 21st: Start 3:37 PM - 3:49 PM - Gap to Next 3 minutes 22nd: Start 3:52 PM - 4:04 PM - Gap to Next 3 minutes 23rd: Start 4:07 PM - 4:18 PM - Gap to Next 3 minutes 24th: Start 4:21 PM - 4:33 PM - Gap to Next 4 minutes 25th: Start 4:37 PM - 4:48 PM - Gap to Next 3 minutes 26th: Start 4:51 PM - 5:17 PM - Gap to Next 3 minutes 27th: Start 5:20 PM - 5:31 PM - Gap to Next 4 minutes 28th: Start 5:35 PM - 5:45 PM - Gap to Next 3 minutes 29th: Start 5:48 PM - 6:00 PM - Gap to Next 4 minutes 30th: Start 6:04 PM - 6:14 PM - Gap to Next 4 minutes 31st: Start 6:18 PM - 6:30 PM - Gap to Next 5 minutes 32nd: Start 6:35 PM - 6:46 PM - Gap to Next 4 minutes 33rd: Start 6:50 PM - 7:01 PM - Gap to Next 4 minutes 34th: Start 7:05 PM - 7:17 PM - Gap to Next 5 minutes 35th: Start 7:22 - tbd Once the gaps stop, and the fountaining becomes continuous, the large fountains will very soon begin.

Ryan Finlay · 2 months ago