Update: Episode 20 lasts less than 5 hours, but lava geisers reach 500-plus feet at Kīlauea summit

Update at 2:57 a.m. May 7: Just 4 and a half hours. That’s as long as the 20th episode of sustained fountaining lasted in the ongoing eruption inside Halemaʻumaʻu Crater at the summit of Kīlauea volcano on the Big Island.

Fast and furious is still more than appropriate to describe its entirety, but it was definitely also short and sweet.

Episode 20 ended just before 10 p.m. May 6 after geisers of molten rock began ejecting regularly from the north vent in the southwest portion of the crater, producing fast moving lava flows onto the crater’s floor, at about 5:30 p.m.

The episodic summit eruption that started Dec. 23, 2024 — which is confined within Hawaiʻi Volcanoes National Park — is now again paused.

Episode 20 was the shortest sustained fountaining phase of the eruption since it began.

Hawaiian Volcano Observatory reported in a Kīlauea status report at 10:30 p.m. May 6 that lava fountains and flows erupted from the north and south vents, but the north vent was much more active.

Fountains from the north vent quickly reached estimated heights of more than 500 feet, while those from the south vent reached heights of up to about 65 feet.

The observatory estimated that lava flows from Episode 20 covered less than half of the Halemaʻumaʻu Crater floor.

Sustained fountaining was preceded by almost 31 hours of precursory low-level activity that included gas-pistoning events in the north vent that produced low lava dome fountains, overflows and drainbacks, as well as sluggish lava flows from the south vent.

The end of Episode 20 was accompanied by a rapid change in summit tilt from deflation to inflation, along with a rapid decrease in tremor. The Uēkahuna tiltmeter at the summit of Kīlauea recorded about 6 microradians of deflation between the start and end of this fountaining episode.

No changes have been detected in the volcano’s East Rift Zone or Southwest Rift Zone.

Kīlauea’s Volcano Alert Level remains at Watch and its Aviation Color Code at Orange.

Hawaiian Volcano Observatory continues to closely monitor Kīlauea and is in contact with Hawaiʻi Volcanoes National Park as well as Hawai‘i County Civil Defense about eruptive hazards, which continue to include the volcanic haze called vog and volcanic fragments such as Pele’s hair tephra.

The observatory will issue an eruption update later today (May 7) unless there are significant changes before then.

Original post at 7:56 p.m. May 6: Fast and furious.

That’s the best way to describe the onset of Episode 20 of the ongoing eruption inside Halemaʻumaʻu Crater at the summit of Kīlauea volcano on the Big Island.

Sustained lava fountaining began at about 5:30 p.m. May 6 after the north vent in the southwest portion of the crater transitioned from cyclic gas-pistoning to continuous eruption of the molten rock geisers that grew rapidly in vigor and height.

By the time Hawaiian Volcano Observatory issued its volcano status at just before 6:30 p.m., fountains were already reaching heights of greater than 500 feet and feeding fast moving lava flows that were covering the crater floor, including a flow that poured over the south vent.

The south vent was not showing any signs of increased activity.

A rapid change in summit tilt from inflation to deflation along with a rapid increase in tremor accompanied the new eruptive activity.

The Uēkahuna tiltmeter at the summit had recorded about 8 microradians of inflationary tilt between the end of Episode 19 and the beginning of Episode 20 fountaining.

Episode 20 was preceded by just fewer than 31 hours of precursory low-level activity that included gas-pistoning events in the north vent that included low lava dome fountains, overflows and drainbacks, as well as sluggish lava flows from the south vent.

Precursory activity began just before 11 a.m. May 5 with the onset of cyclic gas-pistoning in the north vent. About 30 gas-pistoning cycles occurred sequentially between 10:49 a.m. and 6 p.m. before diminishing.

Intermittent gas-pistoning had returned and was ongoing by 10 a.m. May 6.

Strong glow was visible from both vents overnight May 5-6.

Episode 20 low-level precursory activity was less consistent than Episode 19 precursory activity. The main fountaining phase of the previous eruptive episode was preceded by 26 gas-pistoning cycles that happened sequentially during a period of 9 hours.

In comparison, Episode 20 precursory activity lasted more than 30 hours, and included cyclic as well as intermittent gas-pistoning events.

Each episode of Halemaʻumaʻu lava fountaining since the beginning of the episodic summit eruption Dec. 23, 2024, has continued for between 13 hours and 8 days. Eruptive episodes have been separated by pauses lasting from less than 24 hours to up to 12 days.

No changes have been detected in the East Rift Zone or Southwest Rift Zone have experienced no changes.

All eruptive activity is contained within Hawaiʻi Volcanoes National Park.

Kīlauea’s Volcano Alert Level remains at Watch and its Aviation Color Code at Orange.

Hawaiian Volcano Observatory continues to closely monitor Kīlauea and will issue an eruption update tomorrow morning unless there are significant changes before then.

The observatory also is in contact with the national park and Hawai‘i County Civil Defense about eruptive hazards, which continue to include volcanic gases, primarily sulfur dioxide that reacts with the atmosphere to create the volcanic haze called vog, and strands of volcanic glass called Pele’s hair as well as other volcanic fragments such as tephra, often produced by lava fountaining.

Click here for additional discussion about Kīlauea hazards.

Visit the Hawaiʻi Volcanoes National Park website for visitor information.