The number of VLP seismic events (standard values 5-12) is medium, 11.7 events/hour.

The amplitude of seismic tremor is medium.

The infrasonic activity is medium. The acoustic pressure of explosions is medium, 1 bar (standard values <1 bar). The amplitude of puffing is medium, ~50 mbar.

Tiltmeters analysis measures, at 19:55UTC of yesterday,, 1.1 urad of deformation at OHO tiltmeter (see Comunicato_UNIFI_20240209).

Thermal activity of explosive events is medium. The number of thermal transients in the NE sector of the crater (standard = 100) is high, 178. The amplitude of thermal transients is low, 5 ºF. Exit velocity of pyroclasts, estimated through thermal camera analysis, is medium, 25 m/s.

MODIS thermal anomalies are low: 1 MW (12:20 UTC yesterday).

Rockfall activity: no rockfalls detected.

SO₂ flux in the NE sector of the crater terrace is medium, 94 t/d

CO₂ flux based on the C/S is not available

Indice di Attività Vulcanica: medium

• Seismic (VLP) rate MEDIUM
• Seismic tremor MEDIUM
• Puffing MEDIUM
• Acustic pression of explosions MEDIUM
• Thermal activity MEDIUM
• SO₂ flux MEDIUM
• CO₂ flux not available
• Rockfall activity LOW

The volcanic activity at Stromboli in the last 24h has been punctuated by a major explosions occurred at 19:55UTC at SW crater sector which generated a 1.22*10-5 m VLP amplitude and 1.1 urad of deformation (see Comunicato_UNIFI_20240209). This events is inserted in a typical activity characterized by strombolian explosions and degassing activity (puffing) mainly located at the SW crater sector. The number of VLP events shows MEDIUM values (11.7 events/hour). Infrasonic activity is characterized by explosions of MEDIUM pressure (0.1 bar) and puffing from MEDIUM to HIGH amplitude (up to 50 mbar). Seismic tremor values are MEDIUM. Thermal activity at the craters is MEDIUM. MODIS/VIIRS images show LOW thermal anomalies (1 MW). The SO2 flux based on the measure of yesterday shows an increase to MEDIUM values (94 t/d). No new measure of CO2 flux is available in the last 24h, based on C/S ratio. Rockfall activity in the last 24h is absent. The volcanic activity index is MEDIUM. NB: Thermal and Infrasonic values could be underestimated due cloud cover.