Seismotectonic model on geological data for 1892 Dulovo earthquake, lower Danube valley

The potentially active faults in the area of Lower Danube Valley between the arcs of Carpathian and Balkan mountain chains are not properly recognized. The epicentre of the only historically known “strange” earthquake on the territory of Bulgaria with a magnitude evaluated at Ms = 7, known as the “1892 Dulovo Earthquake” is situated in this area. The first step for creating a seismotectonic model for this earthquake is the identification of the nearby active fault. The analysis has shown that it is realistic to accept that the earthquake occurred in the frames of the Tutrakan Graben. A fault segment of the Dulovo Fault, the most probably activated during the 1892 Dulovo Earthquake, is recognised. Its length is 42±5 km, and the width is 15±2 km. The offset of the normal faulting from the last seismic events is evaluated at 2 m. Three approaches are used for determination of the maximum magnitude of the earthquake that can be generated. They give Ms in the range between 6.8 and 7.5. The most probable value is 7.0.