This week's report is deliberately tight: only developments supported by the newest responsible-agency material available at publication time are included. The standout changes are Kīlauea's shallow summit intrusion, a brief explosion at Gareloi in Alaska, a short-lived lava overflow at Stromboli and a marked increase in Kanlaon's daily earthquake count.
Kīlauea underwent a shallow east-west-oriented magma intrusion near its existing summit eruption site overnight on 30 September–1 October. HVO recorded rapid deformation, increased summit earthquakes and tremor, but found no evidence that the intruding magma erupted at a new location.
🇺🇸 Kīlauea WATCH · ORANGE
HVO's latest daily update, issued 1 October at 19:05 UTC, reports a shallow magma intrusion beneath the summit region near the existing eruption site. The intrusion was strongest between about 8 p.m. HST on 30 September and 3 a.m. HST on 1 October and had an east-west orientation.
The event produced large rapid summit-tiltmeter displacements, increased summit earthquake activity and stronger tremor. HVO says there is no evidence that magma associated with the intrusion erupted at a new location. North and south vents continued intermittent overflows and spattering. Episode 55 fountaining remains a possibility, but HVO had not declared Episode 55 underway.
🇺🇸 Gareloi ADVISORY · YELLOW
AVO detected a single brief explosion at Gareloi at 15:27 UTC on 1 October. It lasted less than one minute and prompted AVO to raise the Volcano Alert Level from NORMAL to ADVISORY and Aviation Color Code from GREEN to YELLOW.
Cloud cover obscured the volcano, so AVO could not determine whether an ash cloud was produced. The subsequent daily update reported no further signs of unrest.
🇮🇹 Stromboli Short-lived Lava Overflow
INGV reported a lava overflow on the upper Sciara del Fuoco on 1 October. By its 15:54 UTC update the overflow was no longer being fed and was cooling, with monitoring parameters returning to normal activity.
Ordinary Strombolian activity continued from both the North and Centre-South crater areas, with variable spattering from the North crater area. Average volcanic tremor remained within medium values.
🇵🇭 Kanlaon Level 2 · 94 Earthquakes
Kanlaon remains at Alert Level 2 — Increased Unrest. PHIVOLCS' 2 October bulletin records 94 volcanic earthquakes. Sulfur dioxide flux measured on 1 October was 1,955 tonnes/day. Voluminous emissions produced a plume reaching 1,300 m above the crater. Ground deformation continues to show inflation with short-term deflation.
🇮🇹 Etna Latest VONA · ORANGE
Etna produced renewed ash emission on 29 September. INGV briefly raised the aviation colour code to RED before lowering it again. The latest VONA currently listed by INGV is the 29 September 07:51 UTC notice at ORANGE, which states that weak ash emission was still ongoing at that time.
Toulouse VAAC's final advisory at 16:00 UTC on 30 September said no ash cloud was being produced or identifiable in satellite and webcam data, although weak ash remained possible near the volcano. No newer Etna VONA was listed by INGV at publication time.
🇮🇸 Reykjanes — Svartsengi Slow Uplift Continues
IMO's newest Reykjanes assessment was published on 30 September. There is no eruption underway. Slow ground uplift continues at Svartsengi and seismic activity remains low.
Approximately 4 cm of uplift has been measured over the past three months. A new magma intrusion, potentially followed by an eruption along the Sundhnúkur crater row, remains IMO's most likely scenario. The updated hazard assessment says warning time could be short, potentially less than an hour. IMO gives no new accumulated magma-volume figure, so no older figure is presented as current.
🇯🇵 Sakurajima Repeated Ash Advisories
Tokyo VAAC's latest available list shows repeated Sakurajima advisories into 1 October. The most recent listed advisory is VAA 2026/259 at 13:01 UTC on 1 October, following advisories at 02:12, 09:46 and 10:41 UTC that day.
No eruption count, plume height or other figure is inferred from the advisory frequency.
🇵🇭 Mayon Level 2
Today's PHIVOLCS bulletin records 19 volcanic earthquakes, fair crater glow, sulfur dioxide flux of 1,113 tonnes/day measured on 1 October, and a moderate plume reaching 100 m above the crater. Mayon remains at Alert Level 2.
🇵🇭 Taal & Bulusan Level 1
Taal: one volcanic earthquake, SO₂ 346 tonnes/day measured 1 October, moderate 750 m plume and short-term inflation. Bulusan: nine volcanic earthquakes, SO₂ 74 tonnes/day, moderate 100 m plume and short-term inflation. Both remain at Alert Level 1.
📡 What is genuinely worth watching
Kīlauea: consequences of the shallow summit intrusion and whether Episode 55 fountaining begins. Gareloi: whether the isolated explosion is followed by renewed unrest. Kanlaon: the sharp daily earthquake increase while Alert Level 2 remains in force. Stromboli: whether another overflow develops after the 1 October flow stopped being fed.