Search for Traces of Strong Ancient Earthquakes in the Western Caucasus: Archeoseismological Studies in Ancient Gorgippia

The ancient city of Gorgippia is surrounded by well-known (North Black Sea, Kerch, and South Azov) seismogenic zones, all of which are submarine, and only some of their branching faults reach the surface in the coastal zone. On the surface, in the vicinity of the ancient city, there are also seismically active faults and flexure rupture zones, which can generate strong earthquakes. Our investigations in the ancient city of Gorgippia have revealed a number of seismogenic deformations and destructions in its walls: systematic tilts and shifts of the upper parts of the walls, as well as their arc-shaped bends in plan view; breaks of the walls; rotations of walls and other building elements around the vertical axes; and squeezing of the mouths and shafts of water wells. Some of the mentioned deformations could be formed during the strong historical earthquakes in the 3rd and 1st centuries BC, as well as those in the 1st and 3rd centuries AD, and all these seismic events were accompanied by local destructions and fires. Summarizing all materials on historical earthquakes of the Taman Peninsula, the regional seismic potential can be determined by the possible occurrence of a crustal earthquake with M ≥ 7.0 and average recurrence interval of once in few hundred years. Seismic shaking in the source zones of such natural events can be I₀ = IX or even more.