On October 9, 2022, at 9:22 a.m. (7:22 a.m. UTC), Stromboli's volcanic eruption produced a pyroclastic flow along the Sciara del Fuoco. The flow reached the sea in about 26 seconds, impacting the water at about 50 m/s. The impact of the pyroclastic material into the sea generated a small tsunami, recorded at 9:23 a.m. by the four sensors of the two Elastic Beacons* (MEDA) installed on either side of the Sciara del Fuoco. Since July 2019, these sensors detected 4 small tsunamis caused by pyroclastic flows along the Sciara del Fuoco.
The tsunami, generated by a subaerial source (falling pyroclastic material into the sea, in this case) produced an initial positive wave of about +2 cm in amplitude, followed by a negative wave of -5 cm (produced by the pull of water toward the impact zone).
The acquired data, which are consistent among them, can be compared with the images captured by the monitoring cameras at the Sciara del Fuoco. The tsunami propagation speed was about 32 m/s.
The parameters recorded by the sensors not activated the system of Early Warning Tsunami as the 4-5 cm wave (positive); pre-set threshold values for warning, were not reached.
*Elastic Beacons (MEDA) are continuous sea level detection systems, anchored to the seabed and each equipped with two pressure sensors placed at different depths, whose data are transmitted in real time to the Operations Center on the island of Stromboli.