Etna is the clear story of the week. INGV-OE issued a rapid sequence of activity statements as new effusive vents opened at different elevations in Valle del Bove, ash activity fluctuated at Voragine and the aviation colour code briefly reached RED. In Hawaiʻi, Kīlauea remains paused after Episode 53 but summit inflation continues and HVO has narrowed the next likely fountaining window to 22–26 August. Iceland also produced three useful monitoring updates: increasing pressure and seismicity at Svartsengi, the end of the multi-year uplift episode at Askja, and a small glacial outburst signal in Múlakvísl.
Etna dominates this week after multiple new effusive vents opened in Valle del Bove, lava flows reached much lower elevations, and changing summit activity triggered repeated aviation alerts. Kīlauea remains the major forward watch as HVO tracks re-inflation toward Episode 54.
🇮🇹 Etna New Vents · Ongoing Effusion
Etna remained exceptionally dynamic through the week. INGV-OE issued activity statements on 14, 15, 16, 17, 18, 19 and 20 August. On 17 August at 06:09 UTC, a new effusive crater opening was recorded in Valle del Bove at approximately 2,200–2,350 m elevation, producing a lava flow while ash emission from Voragine continued.
The system changed again on 18 August, when INGV reported another effusive vent at approximately 3,100 m in the upper Valle del Bove. By 19 August, field observations showed that this flow had travelled about 500 m and stopped. The older flow fed from the vent near 1,900 m had advanced to around 1,315 m elevation and was stationary and cooling. A superimposed flow remained active, with its front near 1,550 m close to Rocca Musarra.
Voragine alternated between renewed explosive/ash phases and quieter periods. On 19 August INGV observed no explosive activity during its field inspection, only sporadic diluted ash emissions. Tremor peaked around 03:00 UTC before declining later that day. Etna briefly reached RED aviation colour code on 15 and 16 August. The latest published VONA available for this roundup was ORANGE, issued on 20 August. This is the latest published aviation colour code, not a statement that an ash cloud was continuously present; webcam visibility and ash emission can change between VONA notices.
🇺🇸 Kīlauea Episode 54 Building
Kīlauea remains paused after Episode 53, but the summit is re-inflating. HVO's 20 August update places the likely onset of Episode 54 between Saturday 22 August and Wednesday 26 August. The volcano remains at ADVISORY / YELLOW.
Inflation began immediately after Episode 53 ended, although recharge has again been interrupted by unpredictable deflationary steps. Glow has continued from the north and west vents. No significant activity has been noted along the East Rift Zone or Southwest Rift Zone.
HVO also warned that another tropical system may bring torrential rain this weekend; overlap between severe weather and an eruption could create conditions unsuitable for viewing.
🇮🇸 Iceland Three Monitoring Updates
Svartsengi: IMO's 20 August update reports that seismic activity has been increasing and that there are clear signs of increasing pressure in the system. Two earthquakes above M2 were recorded overnight. Magma accumulation beneath Svartsengi continues, and IMO states that the accumulated volume is now greater than before previous eruptions in the current Sundhnúkur activity sequence. The likelihood of a new dyke intrusion and possibly an eruption therefore remains high. This does not mean an eruption has begun or that its exact timing can be predicted.
Askja: IMO reported on 14 August that the uplift which began in 2021 has stopped, with first indications of subsidence. This is a genuine change in the long-running deformation story.
Múlakvísl / Katla area: unusually high electrical conductivity on 19 August was consistent with a small glacial outburst flood. River level had not risen at the time of the report, although IMO said it could rise. Elevated geothermal gas was also measured near the glacier margin. This is a hydrological/geothermal event, not evidence that Katla is erupting.
🌍 Also on the Global Board
Several long-running eruptions and unrest episodes continue to be monitored by their responsible observatories. They are not expanded here unless a material official change was identified for this reporting week; the roundup prioritises verified week-on-week developments rather than repeating unchanged background activity.
📡 What to watch next week
Kīlauea: Episode 54, currently forecast for 22–26 August, though another deflationary step could shift the timing. Etna: whether the overlapping Valle del Bove flows remain fed, whether further vents open, and whether Voragine returns to stronger explosive activity. Svartsengi: any acceleration in seismicity or deformation. Askja: whether subsidence persists now that the 2021–26 uplift has stopped.