Problems of Engineering Seismology: article

High historical seismicity in North Ossetia according to archaeoseismology (on the example of Dzivgis village)
A.M. Korzhenkov 1 V.T. Chshiev 2 A.S. Larkov 1 A.N. Ovsyuchenko 1 D.E. Edemsky 3 A.A. Averin 3 N.V. Andreeva 1
1 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences 2 Centre for Scytho-Alanic Studies of VSC, Russian Academy of Sciences 3 Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences IZMIRAN
Journal: Problems of Engineering Seismology
Tome: 50
Number: 2
Year: 2023
Pages: 76-110
UDK: 551.2/.3
DOI: 10.21455/VIS2023.2-4
Keywords: Dzivgis, Fiagdon, Kurtatin gorge, Caucasus, archaeoseismology, seismic deformations, “stone boxes”, ground stone crypts, Dzivgis medieval rock fortress, medieval church in Dzivgis village
Аnnotation: The analysis of the data obtained and described by us on deformations of building structures indicates the manifestation of seismic events in the area of the village of Dzivgis on the left slope of the valley of the Fiagdon River. The most ancient of them is the horizontal displacement of the buttress wall by 1.2 m. This was the output of a seismic focus to the surface; its magnitude is M ≈ 7 and the intensity of seismic oscillations is IL = IX–X. The earthquake occurred during the VII–XII centuries. The “stone boxes” of Dzivgis are “seated”, broken by cracks, individual stone blocks, walls and steles are tilted and extended, many blocks and steles are thrown out for a considerable distance. The age of the 2nd earthquake is XI–XV centuries. The intensity of seismic oscillations was not less than IL = IX. The axis of maximum seismic oscillations was located approximately along the southeast-northwest line. The age of the 3rd earthquake fits into the age range of the XIV–XV centuries. Severe deformations of the thick and low walls of the Dzivgis crypts can be attributed to the consequences of an earthquake with a seismic intensity of IL = VIII. The direction of seismic oscillations along the north-northeast–south-southwest axis. The next – 4th earthquake damaged the Dzivgis fortress (the age of construction of the XVI–XVIII centuries). Apparently, the extension of its outer wall coincided with the direction of seismic oscillations (along the east-northeast–west-southwest axis), the fortress received significant damage, which forced its defenders to repair the wall, towers and loopholes. The local intensity of seismic oscillations was IL = VII–VIII. However, the repaired fortress was later damaged again, which may have happened during the next earthquake. The 4th earthquake may have damaged the Gutnov family tower, built in the XV–XVI centuries. The tower was mostly repaired, and cracks visible in the walls of the tower to this day appeared in it during the 5th earthquake. The fifth earthquake, apparently, was the cause of the destruction of buildings in the village of Dzivgis. Their age dates back to the XVIII–XIX centuries. However, the foundations of the houses belong to more ancient times, the destruction of the ancient walls on them may have been caused by the 4th or earlier earthquake. The reason for the deformation of the metal cemetery fences was a rockfall. If it was a seismic event, then it happened after 1878. Strong earthquakes, leading to destruction and damage to building structures in the second millennium AD, occur here approximately once every 200 years. The ages, strength and focal areas of strong earthquakes of the past will have to be clarified after studies of medieval monuments on the northern slope of the Caucasian Ridge, as well as regional paleoseismological and historical-seismological studies.