INGV’s weekly bulletin for Stromboli, covering 3–9 August 2026 and issued on 11 August, reported normal strombolian eruptive activity together with spattering in the North crater area and three episodes of lava overflow from the same crater area.Explosion intensity was high in the North crater area and medium-high in the Centre-South crater area. Overall explosion frequency, combining the North and Centre-South crater areas, was at a medium levels.Seismological monitoring parameters did not show significant changes. GNSS and tilt data also showed no significant ground-deformation variations during the week.Volcanological observationsINGV characterized the eruptive activity using surveillance cameras at 190 m above sea level and at Punta dei Corvi. Explosions from the North crater area mainly emitted coarse material, such as bombs and lapilli. In the Centre-South crater area, explosions mainly produced fine material mixed with coarse ejecta.In the North crater area, the average explosion frequency was at medium values, while the intensity remained mostly high. In the Centre-South crater area, the average explosion frequency was medium-low, and the intensity of explosive activity was generally medium-high. The daily hourly average for total explosions from both crater areas was medium.Spattering, meaning the ejection of blobs and splashes of molten lava around active vents, was particularly associated with the N1 vents in the North crater area and accompanied the lava-overflow episodes.Lava overflows from the North crater areaIn addition to ordinary explosive activity, the North crater area produced three lava-overflow episodes on 4 August, 6 August and between 7 and 8 August, during phases of intense spattering from the N1 vents.The first episode began on 4 August at about 03:30 UTC with rheomorphic deposits, where hot erupted material deformed and moved downslope. It evolved into lava effusion from about 07:30 UTC, then slowly and irregularly waned from about 13:00 UTC and ended at about 16:30 UTC.The second episode started at about 04:44 UTC on 6 August, according to surveillance-camera images. INGV described it as a modest lava overflow, which ended at 12:00 UTC the same day.The third overflow began at about 22:30 UTC on 7 August and ended the following day, 8 August, at around 21:00 UTC. It was also a modest lava flow. As with the previous two events, the flow fronts remained confined to the upper part of the Sciara del Fuoco.SeismologyDuring the week, volcanic tremor amplitude remained at medium values. Very-long-period seismic events, or VLPs, occurred at rates between 14 and 16 events per hour.The amplitude of VLP events was generally low, with some medium-amplitude events. Explosion-quake amplitudes were also generally low, with some medium-amplitude events.Because of technical problems, INGV could not estimate the location and polarization of VLP signals. No earthquakes with local magnitude Ml 1.0 or greater were located in the Stromboli island area during the week.Dilatometer strain data did not show significant variations during the week.Ground deformationSignals from the GNSS network did not show significant variations during the reference week. INGV illustrated this with the time series for distance changes between the Timpone del Fuoco and Punta Lena GNSS stations.The tilt network also showed no significant variations during the week. INGV reported the Elipista tilt station as an example.GeochemistryParameterObservationSO2 fluxThe total daily average SO2 flux from the northern and southern crater areas was at a medium level.Soil CO2 flux, Pizzo area (STR02)No update was available because of technical problems. The latest validated measurements, from 25 July, were high.CO2/SO2 ratio in the plumeDaily averages remained in the medium range during the week, with a slight exceedance of the high-value threshold. The latest validated daily average, on 9 August, was 6.5.Helium isotope ratio (R/Ra) in the thermal aquiferNo new update was available. The latest value, from sampling on 28 July 2026, had decreased from the previous sample but remained high.Soil CO2 flux, San Bartolo areaResidual CO2 flux recorded at the Mofete site and corrected for environmental parameters was high to very high during the last week.Satellite observationsSatellite monitoring showed generally moderate thermal activity at the summit during the effusive events of 4 August, 6 August and 7–9 August. INGV used multispectral MODIS, VIIRS, Sentinel-3 SLSTR and MTG-FCI imagery, among other satellite data.The maximum radiant power was about 87 MW, measured by SLSTR at 09:30 UTC on 4 August during the lava overflow. The latest recorded heat-flux value, at 08:10 UTC on 11 August, was low at about 8 MW according to FCI data.The effusive events had time-averaged discharge rates of 0.70 ± 0.35 m³/s on 4 August at 14:15 UTC (MODIS), 0.23 ± 0.11 m³/s on 6 August at 11:24 UTC (VIIRS), and 0.45 ± 0.23 m³/s on 8 August at 00:48 UTC (VIIRS).Sentinel-2 imagery showed thermal anomalies of about 0.009 km² in the crater area on 30 July at 09:50 UTC, also observed in the subsequent 4 August acquisition and associated with the lava overflow. Because of full or partial cloud cover, INGV could quantify the full areal extent of the thermal anomalies only for the 4 August event. At 09:50 UTC that day, the lava field covered about 0.05 km² and reached an elevation of about 640 m above sea level.Thermal anomalies associated with the 7–9 August effusive activity were still partly visible in Sentinel-2 MSI imagery from 9 August at 09:50 UTC, though cloud cover limited observations. INGV noted that poor visibility during the week may have affected the satellite-image analysis.Expected scenariosINGV indicated the continuation of ordinary strombolian activity, possibly coupled with lava flows along the Sciara del Fuoco from crater overflows. Such activity may be accompanied by rockfalls or debris avalanches along the Sciara del Fuoco.If lava reaches the sea, hydro-magmatic explosions caused by interaction between lava and seawater may occur, with blocks potentially thrown up to a few hundred metres from the coast and dispersion of volcanic gas and/or ash. INGV also noted that explosions stronger than ordinary activity cannot be excluded.INGV stressed that changes in monitored parameters could lead to different hazard scenarios. At Stromboli, some phenomena can occur without warning or evolve rapidly and unexpectedly, so the hazard level is never zero.