Palaeoseismic events in karst terrains along the northern Bulgarian Black Sea coast

The study of the palaoseismic events in the karst terrains of the Bulgarian Black Sea coast is a very important up-to-date problem. The investigated r egion is one of the highest-energy regions in Bulgaria with established and recorded catastrophic historic and contemporary earthquakes. The terrain i s subjected to the influence not only of its own earthquake foci but also o f those in Romania and Russia. The palaeoearthquakes that caused considerab le disturbances in the karst terrains along the Northern Bulgarian Black Se a coast have left significant traces. They caused disturbances in the envir onment and the relief (rearrangement of the surface and ground water karst basins, partially or entirely collapsed caves, deformed caves, oil, gas and salt intrusions and gravitationally formed caves). The ecological conseque nces in historic and contemporary aspects were catastrophic. The palaeoseis mic dislocations were formed as a result of global, regional and local geod ynamic events related with the destruction of the Moezian platform and the regional extension of the Black Sea basin. The time of their display and th eir spatial interrelations were established as a result of complex investig ations accompanied by original documents.