The marsh has a variable water regime and irregular shape . Its area increases in spring and almost dries in summer and autumn . The marsh had dried completely twice , in 1991 and 2012 . In May 2012 , immediately after the 2012 Pernik earthquake , the marsh began to rapidly dry up until it disappeared completely in July 2013 . The cause was a shift of the earth layers of the local karst rocks in the aftermath of the earthquake
2012 Pernik earthquake
2012 Pernik earthquake
Aldomirovtsi Marsh