A week of two new volcanic developments on opposite sides of the world. Kīlauea Episode 50 produced the tallest fountains of the entire 2026 eruption cycle — approximately 1,000 feet from the north vent on 27 June — and HVO has since noted a new localized subsidence feature on the western floor of Halemaʻumaʻu. On Sicily, Etna opened a sub-terminal effusive vent at the base of the Voragine crater on 26 June, with lava flowing into the upper Valle del Bove and ongoing as of today. Both are worth watching closely.
Episode 50 was the biggest episode of 2026. Peak north vent fountains reached approximately 1,000 feet — almost double the 540 metres of Episode 43, previously the cycle's record. Lava covered more than 50% of the Halemaʻumaʻu crater floor. After Episode 50 ended, HVO noticed and reported a localised area of subsidence on the western floor. They have reoriented the V1cam to study it and are watching closely.
🇺🇸 Kīlauea Advisory · Yellow
Episode 50 of the Halemaʻumaʻu eruption began at approximately 10:10 AM HST on 27 June, after precursory north vent overflows began in the small hours of that morning. North vent fountains grew rapidly, peaking at approximately 1,000 feet (305 metres) between 11:00 AM and noon — the highest lava fountains of the entire 2026 eruption cycle, and a significant step up from the ~700 ft peaks of Episodes 46–49. Peak effusion rate was approximately 330 cubic metres per second, slightly higher than recent episodes. Northeast surface winds directed tephra and volcanic gas to the southwest of Halemaʻumaʻu; a light fall of Pele's hair was reported from the town of Pāhala in Kaʻū, roughly 30 km from the vents. Tephra was mostly restricted to the closed area of Hawaiʻi Volcanoes National Park. Fountaining ended abruptly at 5:10 PM HST after approximately seven hours. The UWD tiltmeter recorded 15.3 microradians of deflationary tilt during the episode. Lava flows covered more than 50% of the Halemaʻumaʻu crater floor. HVO lowered the alert level back to Advisory/Yellow at 6:59 PM.
Two post-episode developments are worth noting. First, on 1 July HVO published an observatory message reporting a localized area of subsidence on the western floor of Halemaʻumaʻu. The V1 webcam has been reoriented to focus on this area for at least a few days while scientists assess what it represents. Subsidence features on the crater floor can reflect withdrawal of lava from near-surface conduits after an eruptive episode or settling of the lava lake floor. Second, reinflation has been slower than after previous episodes — a low-frequency seismic pulsing pattern that began when Episode 50 ended has continued, and the inflation rate has been lower, which HVO says is probably delaying the onset of Episode 51. The current Episode 51 forecast window is 7–14 July, wider than recent weeks.
🇮🇹 Etna Effusive · Active
Mount Etna opened a new sub-terminal effusive vent on 26 June 2026, at the eastern base of the Voragine summit crater in the upper Valle del Leone — part of the upper Valle del Bove — at an altitude of approximately 3,000 metres above sea level. INGV's Osservatorio Etneo in Catania confirmed the vent and the associated lava flow. The flow has been moving eastward into the upper Valle del Bove, which is uninhabited terrain. As of the INGV update covering 2 July, the eruption is continuing: lava emerges from the Voragine summit vent at approximately 3,030 m altitude, with flow fronts at altitudes of approximately 2,750 and 2,700 metres. No explosive activity has been observed from the Voragine crater since 27 June. Volcanic tremor amplitudes have been at average levels throughout the week.
This eruption is distinct from Etna's typical paroxysmal episodes — there is no tall ash column or lava fountaining involved. This is a purely effusive event: a slow, relatively low-volume lava flow draining from a vent near the summit and advancing down the eastern slope into the Valle del Bove. Because the Valle del Bove is an uninhabited topographic depression on Etna's eastern flank, there is no immediate threat to inhabited areas or infrastructure. INGV have also reported that a large crack has been observed at the top of the Voragine crater — the crack extends from the crater rim and descends along the right flank. This structural feature may be related to the opening of the effusive vent and is being monitored. Etna's Strombolian activity at the New Southeast Crater (NSEC) had also increased during 14–18 June with lava overflows toward the southeast, before this new Voragine vent opened.
🇷🇪 Piton de la Fournaise Vigilance · Building
Piton de la Fournaise continues to show the sustained dual-source GNSS inflation that has now persisted for more than two weeks without eruption. As of the most recent OVPF bulletins available at time of writing — confirmed through 23 June — both summit GNSS stations and far-field GNSS stations are inflating simultaneously, with elevated CO₂ ground flux at the PCRN and GITN monitoring stations. This is the most sustained pre-eruptive signal of the entire 2026 eruption cycle. The system has now been inflating on both shallow and deep sources since at least 15 June without triggering an eruption — an unusually extended build-up by Piton's standards. OVPF are monitoring 24 hours a day. The alert level remains at Vigilance. A fifth eruption of 2026 at Piton continues to build.
🇮🇸 Iceland — Svartsengi VALS 2 · Orange
The IMO published its updated hazard assessment for the Svartsengi volcanic system on 30 June 2026 — the day the previous assessment expired. The new assessment extends the validity period to 30 September 2026. The risk assessment is unchanged: continued slow magma accumulation ending with a new magma flow and possibly an eruption remains the most likely scenario. Ground uplift and magma accumulation at Svartsengi continue at a steady pace, with the average rate of accumulation in recent weeks remaining stable. Seismicity in the Sundhnúkur crater row and near Grindavík remains relatively low and similar to recent weeks, with no significant changes recorded. The most recent confirmed magma volume figure is approximately 27.5 million m³ from the 9 June IMO update — the highest accumulation recorded between eruptions in the Sundhnúkur series. Warning times in previous events in this series have ranged from 20 minutes to just over four hours.
🇵🇭 Mayon Alert 3 · 175+ days
Mayon's effusive eruption has now run for more than 175 consecutive days. The most recent PHIVOLCS bulletin available, from 22 June, confirms the eruption is continuing with lava effusion, Strombolian activity, rockfalls, and gas-and-ash plumes. Lava flow lengths remain unchanged at 3.8 km (Basud), 3.2 km (Bonga), and 1.8 km (Mi-isi). Alert Level 3 and the 6 km Permanent Danger Zone remain in force. This is now among the longest single effusive phases in recent Philippine volcanic history. There is no indication of any imminent change in eruptive behaviour.
📡 What to watch next week
Kīlauea Episode 51 — the forecast window is 7–14 July. Reinflation has been slower than after previous episodes; HVO will narrow the window as inflation data allows. The western floor subsidence noted on 1 July is also worth tracking — V1cam is pointed at it and HVO will issue updates if the feature develops. Etna's Voragine vent — the lava flow into Valle del Bove is ongoing. Watch for any increase in effusion rate or for Strombolian activity returning to the Voragine crater, which could transition this from a quiet effusive event to something more energetic. The structural crack at the Voragine rim is also being monitored. Piton de la Fournaise — dual-source inflation for 18+ days. Monitor OVPF daily bulletins at ipgp.fr. Any seismic swarm beneath the summit would be the next escalation signal. Iceland — the new IMO hazard assessment is now published at en.vedur.is, valid to 30 September. Risk unchanged — slow accumulation toward likely eruption. Seismicity still low.
Mayon — 175+ days, no change. This eruption is establishing itself as one of the longest recent effusive phases at the volcano.