The size of the symbols indicates earthquake magnitude, the color indicates the focal depth: shallow: 0–75 km (red), medium depth: 75–200 km(green). Source: SHEBALIN,N.V., LEYDECKER,G., MOKRUSHINA,N.G., TATEVOSSIAN,R.E., ERTELEVA,O.O. & V.YU.VASSILIEV (1997): Earthquake Catalogue for Central and Southeastern Europe 342 BC - 1990 AD. -- Final Report to Contract ETNU - CT 93 - 0087 (submitted to EU for publication).

Source: BGR