These two listed events may be describing the same earthquake. Nicholas Ambraseys in his Earthquakes in the Mediterranean and Middle East: A Multidisciplinary Study from 2009, gives March 1267, but goes on to say "Much of the information about this event comes from a contemporary history that describes the effects of the earthquake in some detail (Pachymeris, i. 355–356). It places the event in the month of Kronios, although no year is given. Internal evidence suggests that the earthquake occurred between 1267 and 1273, but it's hard to decide which of these years is correct. Ducellier places this earthquake in July–August 1267 (Ducellier 1980, 176,179.206,219,292,413,424,525). Although the year he deduces from a thorough study of his sources is more plausible that that proposed by others, he fails to observe that the month of Kronios in Pchymeris's usage of the Greek calendar corresponds to March". Here's a link to the book, but you'll need to search on "1267" to find the right page - there are no page numbers. The SHEEC catalogue gives an M 6.7 earthquake at Durres in March 1270, which is in the middle of that range. I would combine the two with a note that explains the issue. Mikenorton (talk) 23:01, 1 December 2019 (UTC)Reply
