This Week
in Fire

This week's monitoring story is Piton de la Fournaise. After months of intermittent signals — brief inflation here, geochemical quiet there — OVPF's daily bulletins from 15 through 18 June all confirm the same thing: both the summit GNSS stations and the far-field GNSS stations are recording inflation simultaneously. Shallow source pressurising, deep source pressurising, together and sustained. That is the pre-eruptive signature. Meanwhile Kīlauea Episode 49 came and went on 14 June without drama, and Episode 50 is on track for next week.

🇷🇪 Piton de la Fournaise Vigilance · Building

The monitoring picture at Piton de la Fournaise has changed markedly this week. OVPF's daily bulletins for 15, 16, 17 and 18 June all carry the same finding: summit area GNSS stations are recording inflation — indicating pressurisation of a shallow source — and far-field GNSS stations are recording inflation — indicating a pressurised deep source. Both sources are inflating simultaneously and the signal has persisted for at least four consecutive days as of this report. This is the most sustained and complete pre-eruptive GNSS signature Piton has shown since before the February 2026 eruption.

To put this in context: on 29 May, both sources briefly inflated together before going quiet again by 1 June. Through early June, OVPF reported only elevated CO₂ at ground stations with no GNSS signals. The resumption and persistence of dual-source inflation from 15 June onwards is a meaningful change. During the 2026 eruption cycle, OVPF have typically observed this combination for days to weeks before eruptive activity begins. The alert level remains at Vigilance — the tier below Alert 2-2 — but OVPF's 24-hour monitoring team will be watching closely. If seismicity begins to increase beneath the summit, that would be the next escalation signal. Piton has now produced four eruptions in 2026; the fifth may not be far away.

🇺🇸 Kīlauea Advisory · Yellow

Episode 49 of the Halemaʻumaʻu eruption ran cleanly and without community impact. Precursory activity began at 4:10 AM HST on 14 June with low dome fountains from the north vent — 3 to 5 metres high feeding short flows. A second overflow followed from 5:59 to 7:04 AM. Sustained lava fountaining began at 9:36 AM HST, approximately five hours after the first precursory overflow. North vent was the sole fountaining vent throughout; the south vent did not participate. Fountains reached a maximum height of approximately 210 metres (688 feet). Ground-level winds were from the north-northeast, directing material to the southwest; higher-altitude winds were light and variable. Tephra fall was restricted to the closed area of Hawaiʻi Volcanoes National Park. No tephra was reported at any public viewing location — Uēkahuna bluff, Keanakākoʻi overlook, or Volcano House. The episode ended abruptly at 5:05 PM HST after 7.5 hours. Lava flows from the episode covered 40–50% of the Halemaʻumaʻu crater floor.

Reinflation began immediately after Episode 49 ended and has been tracking steadily. As of the 18 June HVO daily update — the most recent at time of writing — summit inflation, vent glow and flaming, and degassing continue. HVO's forecast models indicate Episode 50 onset is most likely 25–26 June, within a window of 23–27 June. Both vents are currently glowing, with flames visible from the south vent overnight. This is the 49th episode of the eruption that began on 23 December 2024.

🇮🇸 Iceland — Svartsengi VALS 2 · Orange

No new IMO update has been published since the 9 June briefing that reported 27.5 million m³ of magma beneath Svartsengi — the highest accumulation in the history of this eruption series. The figure continues to rise. Ground uplift is continuing at approximately 2 cm per month, seismicity along the Sundhnúkur crater row and near Grindavík remains low, and the most likely scenario — magmatic dike propagation toward the Sundhnúkur crater row — has not changed. What is new is the calendar: the IMO's current hazard assessment expires on 30 June 2026. A new assessment covering July onwards must be published in the next 11 days. Given the record accumulation and the longest pause in the Sundhnúkur series, the revised assessment will be watched carefully. We have dedicated coverage of the Iceland situation in our 31 March update and 28 April update.

🇵🇭 Mayon Alert 3 · 165+ days

Mayon's effusive eruption has now run for more than 165 consecutive days. The GVP/Smithsonian WVAR for the week ending 17 June (sourced from PHIVOLCS) confirms the eruption continued during 10–17 June, characterised by lava effusion, periodic pyroclastic density currents, incandescent rockfalls, ash-and-gas plumes, and occasional minor Strombolian activity. Alert Level 3 was confirmed by PHIVOLCS as of 17 June. Lava flow lengths remain unchanged: 3.8 km in the Basud Gully, 3.2 km in the Bonga Gully, and 1.8 km in the Mi-isi Gully — no further advance recorded following the two consecutive weekly advances in May. The 6 km Permanent Danger Zone remains in force. There is no current indication of any imminent change in eruptive behaviour.