Problems of Engineering Seismology: article

Аnnotation: We conducted archaeoseismological studies in the Djanavara Monastery Complex in 2019. It consists of early medieval buildings of different ages, the main of which was the church. The church and the atrium were first badly damaged and then destroyed. There were attempts to repair them, as evidenced by the laying of a doorway in the north wall of the atrium. The age of this seismic event may coincide with the destruction of the “second” Episcopal Basilica of Varna, also built in the second half of the 5th century AD. This earthquake took place several decades later. Judging by the kinematic indicators in the building structures, the source of seismic movements, apparently, was located north-north-east of the Episcopal Basilica of Varna and, accordingly, of the Djanavara monastery complex. In this direction, the largest seismotectonic node is located at the intersection of sub-latitudinal faults with the Shabla-Kaliakrenseismogenic zone. Subsequent renovation of the Djanavara Church and the construction of poor-quality buildings around it took place after this seismic event. However, even in these - later walls, we see traces of younger seismic deformations. They are evidenced by numerous buttress walls attached to the walls that survived the second earthquake. Judging by the crepid walls attached to the original meridional walls from the east and west, the seismic movements of the second earthquake propagated along the east-west axis. The third seismic event put an end to the activity of the monastery complex. It can be seen that the repaired walls of low quality underwent deformation again: the later masonry, which covered the doorway, moved outward, and there was also a joint deformation of the meridional wall and its buttress. The movement of the latest masonry to the west testifies to the source of seismic vibrations of this time, located to the west of the Djanavara complex. However, meridional walls have a case of clockwise rotation of their parts, while a perpendicular wall - counterclockwise. Such a systematic deformation presupposes the location of the seismic focus not strictly to the west of the monastery complex, but to the southwest, which coincides with the direction to the focus, which we determined for the deformations in the episcopal basilica of Varna. Some researchers believe that the Djanavara monastery complex was destroyed and finally abandoned in 614-615 AD during the Avar-Slavic invasion. However, there are materials indicating that residents left ancient Odessa even before the attack, most likely due to a strong (third in our case) earthquake, during which the entire city was engulfed in fires, and many buildings were destroyed. We were unable to accurately estimate the local seismic intensity for each of the three described ancient earthquakes, however, such significant deformations as systematic inclination and extension of walls, as well as turns of their parts around the vertical axis, indicate that the intensity of seismic vibrations during the studied earthquakes reached I