This Week
in Fire

Kīlauea moved decisively from forecast mode to eruption mode this week: Episode 53 ran for 9.6 hours, with north-vent fountains reaching about 150 m and roughly 4.6 million m³ of lava erupted. Etna stayed in a sustained high-activity phase through 13 August, with effusion continuing from vents at about 2,750 m and 1,900 m and the leading active front near 1,340 m. Mayon is now at Alert Level 2, marking a notable easing from the stronger unrest highlighted in recent roundups.

🇺🇸 Kīlauea Episode 53 · Completed

Episode 53 of Kīlauea's ongoing Halemaʻumaʻu eruption began at 3:45 p.m. HST on 12 August and ended abruptly at 1:23 a.m. HST on 13 August, after 9.6 hours of continuous lava fountaining. The episode was dominated by the north vent, which reached a maximum fountain height of approximately 500 ft (150 m) above ground level. The south vent never developed sustained fountaining during the episode, although it produced several overflows, while the new west vent — formerly referred to as the collapse pit — produced short lava flows and periodic flames that became especially visible after 7:00 p.m. HST.

The eruption rate was substantial. HVO estimated a peak instantaneous effusion rate of approximately 230 m³/s at around 5:15 p.m. HST, with an average rate of about 135 m³/s across the full episode. In total, approximately 4.6 million m³ of lava was erupted, covering roughly 40–50% of the Halemaʻumaʻu crater floor. The Uēkahuna tiltmeter recorded about 14 microradians of deflationary tilt during Episode 53.

Precursory activity began hours before sustained fountaining. Small glimpses of spatter appeared after 10:00 a.m. HST on 12 August, becoming more persistent after 11:04 a.m., followed by a sequence of short-lived overflows from the north vent. Output increased markedly at 1:45 p.m. HST as summit tilt switched to deflation, producing a broad overflow that rapidly extended more than 600 m from the vent. Large south-vent overflows followed at 3:26 p.m. and 3:38 p.m., with additional activity from the west vent shortly before the main fountaining phase began.

The north vent fountain peaked at approximately 500 ft (150 m) around 5:00 p.m. HST, feeding a gas-and-ash plume that reached a maximum altitude of about 18,000 ft (5,500 m) above sea level. Lower-level winds carried gas, fine ash and Pele's hair toward the southwest, while higher-altitude winds transported finer material westward toward the summit region of Mauna Loa. Tephra larger than ash size fell within roughly 1–2 km of the vents, entirely inside the closed area of Hawaiʻi Volcanoes National Park.

Fountain heights gradually declined through the evening, dropping to around 350–400 ft (110–120 m) by 6:40 p.m., near 330 ft (100 m) shortly before 10:00 p.m., and around 300 ft (90 m) by midnight. During the final half-hour, fountains varied between roughly 100 and 200 ft (30–60 m) before the eruption ended abruptly at 1:23 a.m. HST. The final four minutes were marked by gas jetting and flames from the north vent.

Episode 52 had ended on 29 July, beginning the inter-episode recharge period that eventually led into Episode 53. At the moment Episode 53 ended, summit deformation switched abruptly from deflation back to inflation. HVO stated that this change indicates that another lava-fountaining episode is likely, continuing the episodic eruption sequence that began in December 2024.

🇮🇹 Etna Effusive + Explosive Activity

Etna remained one of the week's major stories as activity continued after the 6–7 August Voragine paroxysm. In INGV-OE Volcanic Activity Statement Update No. 16, issued at 17:37 UTC on 13 August, surveillance imagery and field inspections confirmed that effusive activity was continuing from eruptive vents at approximately 2,750 m and 1,900 m elevation. Effusive activity from the 2,090 m vent had ceased.

The most advanced active lava fronts associated with the 1,900 m vent were at approximately 1,340 m elevation at 09:45 UTC on 13 August, slightly above Rocca Capra in Valle del Bove. This represents the latest confirmed position of the active lava front in the official INGV update used for this roundup.

At the summit, conditions intensified again late on 13 August. INGV reported that explosive activity at Voragine increased significantly from 16:55 UTC, producing ash that dispersed into the southern quadrant. Volcanic tremor had remained in the high range throughout the day and showed a clear increase from around 10:00 UTC, reaching a peak between approximately 12:00 and 15:00 UTC before continuing at high values with modest fluctuations.

The tremor source centroids were located beneath the Voragine crater area and north of Bocca Nuova, at around 3,000 m above sea level. Infrasonic activity also rose progressively through the day and increased markedly from around 10:00 UTC, reaching a very high level. Most infrasonic events were located at Voragine, with amplitudes increasing from low to high values; additional high-amplitude sources were recorded at the Northeast Crater. INGV reported no significant changes in ground deformation signals.

🇵🇭 Mayon Alert Level 2 · Decreased Unrest

Mayon is now at Alert Level 2, which PHIVOLCS describes as a moderate level of unrest. The 14 August bulletin lists the state as Decreased Unrest. Lava flows remain emplaced in the Basud, Bonga and Mi-isi gullies, with reported lengths of approximately 3.8 km, 3.2 km and 2.7 km respectively.

This is an important change from the stronger unrest highlighted in July. Alert Level 2 does not mean the volcano has returned to normal, and official exclusion-zone and hazard guidance remains in force.

🇷🇪 Piton de la Fournaise Vigilance · Quiet Summit

Piton de la Fournaise remains at Vigilance, but the deformation picture has changed from the dual-inflation story followed earlier in the summer. OVPF's validated July bulletin says pressurisation of the shallow reservoir stopped during July; summit inflation ended and was followed by deflation of the edifice. Deep seismicity persisted, which OVPF notes may reflect fluid movement at depth.

The preliminary bulletin for 13 August recorded no shallow summit volcano-tectonic earthquakes, one deep VT event and one rockfall. There was no eruptive activity in July. The correct reading now is continued Vigilance with a quiet summit and some deeper activity — not an imminent-eruption countdown.

🇮🇸 Iceland — Svartsengi Steady Accumulation

There was no major change in the Svartsengi assessment this week. IMO's current modelling places the volume change beneath Svartsengi between approximately 27.5 and 29.1 million cubic metres. Ground uplift and magma accumulation continue, with the average accumulation rate described as steady. Seismic activity along the Sundhnúkur crater row and around Grindavík remains low.

IMO's most likely scenario remains continued slow magma accumulation leading eventually to another dyke intrusion and possibly an eruption. The hazard assessment is unchanged and remains valid until 30 September. That makes Iceland a watch rather than a headline this week: the system is still loading, but without the seismic acceleration or rapid deformation that would indicate an immediate transition.