1901 Black Sea earthquake
The 1901 Black Sea earthquake (also known in Bulgaria as the Balchik earthquake) was a 7.2 magnitude earthquake, the most powerful earthquake ever recorded in the Black Sea. The earthquake epicenter was located in the east of Cape Kaliakra, 30 kilometres (19 mi) off northeast coast of Bulgaria.
Source: Wikipedia — 1901 Black Sea earthquake (CC BY-SA 4.0)