1857 Basilicata earthquake

The 1857 Basilicata earthquake (also known as the Great Neapolitan earthquake) occurred on December 16 in the Basilicata region of Italy southeast of the city of Naples. The epicentre was in Montemurro, on the western border of the modern province of Potenza. Several towns were destroyed, and there were around 11,000 fatalities according to official sources, but unofficial estimates suggest that as many as 19,000 died. At the time it was the third-largest known earthquake and has been estimated to have been of magnitude 7.0 on the moment magnitude scale. The principal shock occurred at about 10:15 pm local time on December 16, 1857, with a duration of about 25 seconds. It was preceded by several foreshocks, the largest of which occurred about two minutes before the mainshock. The earthquake was followed by numerous aftershocks, which continued until May 1859, the most damaging of which occurred at about 04:00 local time on December 26. Another damaging aftershock occurred on March 8, 1858. The largest foreshock had a duration of 4–5 seconds and affected the area between Balvano and Marsico Nuovo. The maximum intensity of this shock has been estimated to be in the range VII–VIII on the Mercalli–Cancani–Sieberg scale (MCS), based on comparisons with the shaking experienced at Naples and Lagonegro from earthquakes in 1826 and 1893. The earthquake was felt over a large area, as far away as L'Aquila to the north, Otranto to the east, Cosenza to the south and Ponza to the west. The strongest shaking, estimated as XI MCS, affected Montemurro and Saponara. In both cases the towns were completely destroyed, with only one or two buildings left standing, although severely damaged. Montemurro was particularly affected by fires that broke out after the earthquake. The area affected by shaking of X MCS was large including, Alianello, Atena Lucana, Brienza, Calvello, Castelsaraceno, Marsico Nuovo, Missanello, Paterno, Polla, Sant'Angelo Le Fratte, Sarconi, Spinoso, Tito, Tramutola and Viggiano.