This Week
in Fire

This week sits between Kīlauea episodes — Episode 47 ended at 12:27 AM HST on 15 May after nine hours of north-vent fountaining, and Episode 48 is forecast for the coming weekend. The main scientific story is a shift in Piton de la Fournaise's monitoring data: for the first time since the 2026 eruption cycle began, neither the summit nor far-field GNSS stations are recording any particular signals — a genuine inter-eruptive quiet that is meaningfully different from the deep inflation that had persisted until this week.

🇺🇸 Kīlauea Advisory · Yellow

Episode 47 ended abruptly at 12:27 AM HST on 15 May after nine hours of continuous lava fountaining from the north vent. The episode began at 3:27 PM HST on 14 May following a well-signalled precursory sequence: south vent overflows began at 2:57 AM HST that morning, with six overflow events recorded before 7:00 AM, each lasting 20–30 minutes. The north vent fountain grew steadily and reached a maximum height of around 200 metres (650 feet) by 5:00 PM HST. Around the time peak height was reached, low-altitude winds weakened, causing the ash plume to rise more vertically and then spread radially, sending tephra to several locations around the rim of Kīlauea's caldera. Tephra up to 8 cm in diameter fell in public areas of Hawaiʻi Volcanoes National Park to the northeast. The UWD tiltmeter recorded 15.6 microradians of deflationary tilt during the episode.

Summit reinflation began immediately after Episode 47 ended and has been tracking steadily since. As of the 21 May HVO update — the most recent at time of writing — the latest forecast window for Episode 48 is Sunday 24 May to Tuesday 26 May. Both vents continue to glow overnight, with south vent glow described as brighter than the north. HVO noted a brief period of slight deflationary tilt on 20 May that temporarily interrupted the reinflation trend — potentially a minor DI (deflation-inflation) event — before inflation resumed. HVO has stated that periods of slowed inflation or brief deflation may delay the onset of Episode 48. The 8.4 microradians of reinflation recorded by UWD as of 18 May represents roughly 54% of the 15.6 microradians lost during Episode 47.

🇵🇭 Mayon Alert 3 · 135+ days

Mayon's effusive eruption entered its 131st consecutive day on 14 May and shows no sign of meaningful change. PHIVOLCS reported on 14 May that lava flow collapse-fed pyroclastic density currents were recorded along both the Bonga and Mi-isi gullies at 11:20 PM, alongside minor Strombolian activity at the summit crater photographed between 10:32 and 11:03 PM. Lava effusion continues from the summit crater. Flow lengths in the Basud Gully (3.8 km) and Bonga Gully (3.2 km) remain unchanged, while the Mi-isi Gully flow — which advanced to 1.6 km as reported last week — shows continued activity consistent with ongoing lava supply to that drainage.

PHIVOLCS Director Teresito Bacolcol reiterated this week that PDC events — locally called "uson" — are a normal feature of Mayon's ongoing eruption, driven by lava flow collapse rather than explosive activity. The 6 km Permanent Danger Zone remains enforced. Alert Level 3 is maintained. PHIVOLCS continues to warn that PDCs move at speeds that cannot be outrun and that the southern sector is particularly exposed. With the eruption now in its fifth consecutive month and no reduction in monitoring parameters, there is no indication of an imminent end to the current phase.

🇷🇪 Piton de la Fournaise Alert 2-2 · Genuinely quiet

Something has changed at Piton de la Fournaise this week. Throughout the repose period since the fourth 2026 eruption ended on 12 April, OVPF bulletins had consistently reported that far-field GNSS stations were recording inflation — indicating a pressurised deep source beneath the volcano. That signal has now gone. The 20 and 21 May OVPF bulletins report that neither summit GNSS stations nor far-field GNSS stations are recording any particular signals. CO₂ ground flux at the PCRN monitoring station has been on a decreasing trend since the end of the February–April eruption. Summit fumaroles show only background concentrations of SO₂ and H₂S — below 0.1 parts per million — consistent with the resting phases seen between eruptive cycles. This is the most genuinely quiet state Piton has been in since before the January 2026 eruption began.

This does not mean the system is switching off. Piton de la Fournaise erupts on average roughly twice a year in normal years, and 2026 has already produced four eruptions in less than four months. What this week's monitoring data suggests is that the system has moved into a deeper inter-eruptive phase than previously indicated — one where the shallow and deep sources are no longer showing pressurisation signals. Whether this is the beginning of a longer quiet period or simply a brief lull before the next recharge cycle builds is impossible to say from these data alone.

🇮🇩 Dukono Alert 3 · Ongoing

Dukono remains at Alert Level 3 two weeks after the 8 May eruption that killed three hikers. Body recovery operations were still ongoing last week, with two survivors having voluntarily remained on the mountain to assist search teams. PVMBG has not downgraded the alert level. The volcano — one of Indonesia's most persistently active — remains closed. Our full dedicated report on the 8 May eruption and its aftermath is available here, and will be updated as further official information is confirmed.