Calabrian Earthquake of 1783
February 5 This earthquake, with an estimated magnitude of 7.0, affected a large area including most of the southern Italian peninsula and shook the whole of Sicily.
Many villages were damaged and as many as 180 almost completely destroyed, with more than 25,000 casualties. A tsunami affected the coastline on both sides of the Straits of Messina, destroying the harbour walls at Messina.
Near the epicenter the ground shaking was so intense that people were knocked off their feet and heavy stones were found to be dislodged and overturned. Large landslides caused major destruction at Terranova and Molochio but even well-constructed buildings not thus affected were almost completely destroyed, such as in Oppido Mamertina and Casalnuovo.
The earthquake is thought to have involved rupturing of the Galatro, Cittanova and Sant'Eufemia faults, which form the southeastern boundary to the Gioia Basin.
This magnitude 6.2 event occurred during the night following the first event and struck the area just to the southwest. Most of the damage and casualties appear to have been caused by a tsunami that was set off by a major collapse of Monte Pací into the sea near Scilla shortly after the earthquake. Many of Scilla's residents, frightened by the tremors of the previous day had moved onto the open beach for the night, where they were overwhelmed by the waves. The tsunami caused severe flooding in the town, reaching as far as 200 m inland, and there were more than 1500 deaths.
The earthquake is thought to have involved rupturing of the Scilla fault, which defines the coast around Scilla.
This event occurred at about midday 40 km NE of the first mainshock on the 5th. Severe damage extended 15 km along the front of the Serre Mountains, levelling all the villages between Acquaro and Soriano Calabro.
The earthquake is thought to have involved rupturing of the southern segment of the Serre fault that bounds the Mesima Basin.
This earthquake was the weakest of the sequence and caused relatively little damage.
The earthquake is thought to have involved rupturing of the northern segment of the Serre fault.
The final event of the sequence was of similar magnitude to the first and had an epicenter about 20 km east of the fourth, near Borgia in the Catanzaro Basin. The earthquake lasted for about ten seconds, and many villages were destroyed with many hundreds dead in Borgia, Maida and Cortale. Landslides were common and sand volcanoes were seen, particularly on the banks of the Amato river.
This earthquake has not been tied to a particular fault, but a recent re-evaluation of the intensity data indicates that the isoseismal areas are elongated NE-SW, suggesting faulting of similar trend to that observed for the other earthquakes in the sequence.
At the time of the earthquake, during the night, flames were seen to issue from the ground in the neighborhood of this city towards the sea, where the explosion extended, so that many countrymen ran away for fear; these flames issued exactly from a place where some days before an extraordinary heat had been perceived. After the great concussion there appeared in the air, towards the east, a whitish flame, in a slanting direction, it had the appearance of electric fire, and was seen for the space of two hours.”— Count Francesco Ippolito