Slope Phenomena in the Region of the Historical Monument “The Horseman of Madara” in NE Bulgaria

Abstract

The monument ``The Horseman of Madara{''} (ninth century A.D.) includes a bas-relief and petroglyphs-historical chronology. The both of them are with importance for the ancient Bulgarian history. The monument was carved in the Upper Cretaceous calcareous sandstone of the abrupt Madara Plateau slope. The sandstone is fractured and eroded. The sandstone and the investigated monument lay over the Lower Cretaceous marls and clays. The slope processes take place in the Madara Plateau slope. They represent a significant danger for the monument, subject of study. The contemporary movements along the fractures in the monuments are estimated by the extensometric measurement's monitoring. The extensometric measurements shows significant displacement as result of the 1999 Izmit (Turkey) earthquake (M = 7.4).