Abstract

The intensively developed densely populated parts of the Baikal–Mongolian region (BMR) within the Selenga River basin and the southwestern part of the Baikal seismic zone have been selected for research. Geomorphologically, the territory is located within the Selenga Dauria, which merges with the mountain ranges of Mongolia. Earthquakes constantly occur here, and their strength varies widely, sometimes reaching catastrophic values. The high seismic potential of the region is due to the presence at a relatively short distance of seismically active zones in the north (Lake Baikal) and in the south (Mongolia) and the presence of earthquake epicenters with an energy class reaching 15. The main tectonic elements of the area are the faults that control the Meso-Cenozoic depressions. Fragments of these faults correspond to the zones of occurrence of earthquakes with a magnitude of 5.5–6.0. Therefore, the study of the seismic process, the features of the manifestation of seismicity, and the assessment of the seismic hazard of this territory are currently given special importance. The research results are aimed at developing methods for studying and predicting the seismic effects of large earthquakes in the BMR. As a result, the most probable seismic-soil models are formed for various thicknesses of loose deposits, differing in their composition and state, taking into account the depth of bedrock occurrence. The available seismogeological and geophysical information and the data obtained by us on the study of engineering and seismological conditions for the construction of a number of industrial and civil facilities are used. According to the records of the last large earthquakes by permanent seismic stations, a single initial signal was formed for the accepted level of initial seismicity. When using it for the constructed models and implementing theoretical calculations, a comparative analysis of the effect of near-surface inhomogeneities on the initial seismic signal was carried out using a set of main indicators of seismicity manifestation: seismic characteristics (accelerograms, spectra, and frequency characteristics) and their parameters (maximum accelerations and prevailing and resonant frequencies). The data presented for the prevailing varieties of soils of various conditions lead to the possibility for their use in zoning the seismic hazard of the study area.

中文翻译：

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贝加尔-蒙古地区西南部不同地震及施工地基条件下地震活动性对比评价

摘要

选择色楞格河流域贝加尔—蒙古地区人口密集地区和贝加尔地震带西南部地区进行研究。从地貌上看，该地区位于色楞格达里雅山脉境内，与蒙古山脉融为一体。这里经常发生地震，强度差异很大，有时甚至达到灾难性的程度。该地区的高地震潜力是由于北部（贝加尔湖）和南部（蒙古）的地震活动区距离相对较短，并且存在能量等级达到 15 级的地震震中。该地区的构造要素是控制中新生代坳陷的断裂。这些断层碎片对应着5.5-6.0级地震的发生区。因此，对该地区地震过程、地震活动表现特征以及地震危险性评估的研究目前尤为重要。研究成果旨在开发研究和预测BMR大地震地震影响的方法。因此，最可能的地震土壤模型是针对不同厚度的松散沉积物形成的，其成分和状态各不相同，同时考虑到基岩产状的深度。利用现有的地震地质和地球物理信息以及我们在研究工程和地震条件方面获得的数据来建设一些工业和民用设施。根据常设地震台站最近一次大地震的记录，形成了可接受的初始地震活动水平的单一初始信号。在将其用于构建模型和进行理论计算时，使用一组地震活动表现的主要指标：地震特征（加速度图、频谱和频率），对近地表不均匀性对初始地震信号的影响进行了比较分析。特性）及其参数（最大加速度以及盛行频率和共振频率）。针对不同条件下的主要土壤品种提供的数据使得它们有可能用于对研究区域的地震危险进行分区。