Abstract

We conducted archaeoseismological studies at 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 CE. This earthquake took place several decades later. Judging by the kinematic indicators in the building structures, the source of seismic movements was apparently located north-northeast 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 sublatitudinal faults with the Shabla-Kaliakra seismogenic zone. Subsequent renovation of the Djanavara Church and 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, evidenced by numerous buttress walls attached to the walls that survived the second earthquake. Judging by the buttress 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 low-quality walls were again deformed: the later masonry that covered the doorway moved outward, and there was also a joint deformation of the meridional wall and its buttress. The westward movement of the latest masonry testifies to the source of seismic oscillations of this time, located west of the Djanavara Complex. However, the meridional walls show clockwise rotation of their parts, while a perpendicular wall was rotated counterclockwise. Such a systematic deformation presupposes the location of the seismic source not strictly to the west of the monastery complex, but to the southwest, which coincides with the direction to the source, 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 CE during the Avar–Slavic invasion. However, there are materials indicating that residents left ancient Odessos 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 shifting of walls, as well as rotations of their parts around the vertical axis, indicate that the intensity of seismic oscillations during the studied earthquakes reached I_L ≤ 9 on the MSK-64 scale. The intensity of seismic oscillations may have been enhanced by unfavorable soil conditions at the site of the construction of the Djanavara Monastery Complex.

中文翻译：

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保加利亚瓦尔纳 Djanavara 地区一座早期基督教修道院的地震变形。第 2 部分：调查结果

摘要

2019年我们在Djanavara Monastery Complex进行了考古地震学研究。它由不同时代的早期中世纪建筑组成，其中主要是教堂。教堂和中庭首先遭到严重破坏，然后被摧毁。曾有人试图修复它们，在中庭北墙上铺设了一个门口就证明了这一点。这次地震事件的年代可能与同样建于公元 5 世纪下半叶的瓦尔纳“第二个”圣公会大教堂的毁坏相吻合。这场地震发生在几十年后。根据建筑结构中的运动学指标判断，地震源显然位于瓦尔纳主教座堂的东北偏北，因此也位于贾纳瓦拉修道院建筑群的东北偏北。在这个方向，最大的地震构造节点位于次纬度断层与 Shabla-Kaliakra 地震带的交汇处。在这次地震之后，贾纳瓦拉教堂进行了后续翻新，并在其周围建造了劣质建筑。然而，即使在这些后来的墙壁中，我们也看到了较年轻的地震变形的痕迹，从第二次地震中幸存下来的墙壁上附着的许多扶壁墙证明了这一点。从东、西两面与原经向墙相连的扶壁来看，第二次地震的地震运动沿东西轴线传播。第三次地震事件结束了修道院建筑群的活动。可以看到，修复后的劣质墙再次变形：后来覆盖门口的砖石向外移动，并且子午墙和它的扶壁也发生了联合变形。最新砌体的西移证明了这次地震振荡的来源，位于 Djanavara Complex 以西。然而，子午墙显示其部分顺时针旋转，而垂直墙则逆时针旋转。这种系统性变形假定地震源的位置并非严格位于修道院建筑群的西部，而是位于西南，这与我们为瓦尔纳主教座堂的变形确定的源方向一致。一些研究人员认为，在公元 614-615 年阿瓦尔 - 斯拉夫入侵期间，贾纳瓦拉修道院建筑群被摧毁并最终被遗弃。然而，有材料表明，居民甚至在袭击之前就离开了古老的敖德索斯，这很可能是由于强烈（在我们的案例中为第三次）地震造成的，在此期间，整个城市被大火吞没，许多建筑物被摧毁。我们无法准确估计所描述的三个古地震中每一个的当地地震烈度，但是，诸如系统倾斜和移动墙壁以及其部件绕垂直轴旋转等显着变形表明地震的烈度所研究地震期间的振荡达到在 MSK-64 量表上I _L ≤ 9。Djanavara Monastery Complex 施工现场不利的土壤条件可能增强了地震振荡的强度。