A destructive earthquake occurred two days before the mainshock at 21:00 local time, centered in the Val di Noto. It had an estimated magnitude of 6.2 and a maximum perceived intensity of VIII–XI on the Mercalli intensity scale. Intensities of VIII or higher have been estimated for Augusta, Avola Vecchia, Floridia, Melilli, Noto Antica, Catania, Francofonte, Lentini, Scicli, Sortino, and Vizzini. Augusta lies well outside the main zone of severe shaking; its extensive damage is probably due to its construction on unconsolidated sediments. From the shape and location of the area of maximum damage, this earthquake is thought to have been caused by movement on the Avola fault. Some buildings collapsed in Catania, Vizzini, and Sortini. There were an estimated 200 deaths in both Augusta and Noto.