February 20, 1743 Earthquake: Greece

Earthquake on 9/20 February 1743. A memory note written by a monk in a local ecclesiastic book of the Asomaton Monastery, Lefkada, reads as follows: “Today, 9 February 1743 [O.S.], [20 February 1743, N.S.], Wednesday, an earthquake occurred at ninth hour of the day [i.e., 15:00 local time]; it was so terrible as to cause collapse of all churches in Amaxiki, and all the houses overturned. In Lefkada, some villages were extensively damaged, and fatalities”.

Based on our evaluation, it is very likely that a strong local earthquake caused destruction in Amaxiki at ~3 p.m. on 9/20 February 1743. The damage reported in Preveza and Vonitsa on the mainland could be attributed to the same earthquake. It is not unusual for destructive earthquakes in Lefkada to cause important damage on the mainland, e.g., the earthquake on 7/19 January 1825. At least 3.5 h later, the Strait of Otranto large earthquake completed the damage in Lefkada and possibly on the mainland. The next day, 10/21 February 1743, another damaging earthquake occurred in Lefkada, possibly an aftershock of the previous day’s strong local earthquake, unless Machairas mistook the date of the earthquake that supposedly occurred on 10/21 February 1743. The implication of this scenario is that the General Provvedidor of the Sea, Antonio Loredan, witnessed the cumulative effects of two, possibly three, earthquakes when visiting Lefkada before writing his first and more detailed post-event report dated 16 March 1743. Such a scenario is consistent with the various information sources referring to the earthquake damage in Lefkada and on the mainland during February 1743 and better explains why the damage zone attributed to the Strait of Otranto large earthquake has reportedly been quite extensive. (reference #14265)

Note: reference #14265 lists a separate destructive earthquake (magnitude 6 Mw) on 21 Feb 1743 in the same area; stating “A critical issue is whether the 10/21 February 1743 earthquake is an echo of the earthquake(s) that reportedly hit Lefkada on the previous day”