The Ingv recalls (and reconstructs) the destructive eruption of 40 years ago in Randazzo

CATANIA – Shortly after lunchtime on March 17, 1981, at an altitude of 2,625-2,500 meters, fractures begin to open on the north side of Etna. Thus begins one of the most dramatic and destructive eruptions of Etna in the last centuries. An event that will be of very short duration – only 6 days – but which will develop with an unusually violent and rapid dynamic.

The event was observed and studied by volcanologists from the University of Catania and the International Institute of Volcanology, an institute that merged into the current Etneo Observatory of the Ingv which publishes on the IngvVulcani website a reconstruction by volcanologist Boris Behncke. In just two days, the lava flows flood and devastate woods, cultivated land, vineyards, farmhouses and houses; they cut roads, railways, overwhelming telephone and electricity lines. The flows almost reached the town of Randazzo and the nearby village of Montelaguardia.

In the evening of 17 March a fracture opens at an altitude of 1,800 meters from which a massive lava flow begins to advance very rapidly towards the north, threatening the town of Montelaguardia, a few kilometers east of Randazzo. In the early hours of March 18, the system of eruptive fractures spreads further downwards and in the late morning reaches an altitude of 1400 meters. The main lava flow follows a path that heads between Randazzo and Montelaguardia.

In a few hours, the main flow destroys dozens of country houses and cultivated land and cuts all communication routes: the tracks of the State Railways and the Fce, the State 120 and several other roads. It cuts off the electricity and telephone lines, leaving Randazzo in the dark and isolated. Meanwhile, the propagation of the system of eruptive fractures continues, ending in the afternoon of March 18 with the opening of some small vents at an altitude of 1,250-1,115 meters, from which only smaller volumes of lava come out. The longest arm, on 19 March, reaches the bed of the Alcantara river

Finally, the eruption begins to lose strength, and the flow that is threatening Randazzo slows down, stopping 2 km from the town on 23 March.

The total volume of lava emitted in this eruption is estimated to be around 20-30 million cubic meters, a relatively modest volume, but the effusive rates have reached exceptional peaks of around 600 cubic meters of lava emitted per second.