Modeling of strong ground motion of Baku city on the basis of microseismic data and parameters of scenario earthquakes
Babayev Gulam Rustam oglu
The thesis is devoted to the investigation of spatio-temporal features of seismicity and dynamics of seismic processes in the Absheron on the scenario earthquakes and the simulation of microseismic field soils for the first kilometers of Baku according to the spectral composition of microseismic noise. Thereby the increase of construction works, as well as the the number of new buildings influenced the population increase issue and the safety problem of established infrastructures.The actuality of the paper is stipulated by the need to review the relation of seismic zoning of Baku in the context of increased seismic activity over the last decade. In order to study the dynamics of a sequence of seismic events in Absheron Balkhan threshold, determination of process of distribution of earthquakes and identification of various features of the seismic regime of the explored field, the clusterization and Alan factor analysis, as well as the technique of multidimensional grouping of seismic events for the period from 1842 to 2015 has been done. The cluster analysis and multidimensional grouping method allowed us to estimate the time range in dynamic mode of seismic sequence in the area of research, identifying patterns that precede and/or accompany a major seismic event and to more accurately set the frequency of earthquakes and interrelatedness.According to the existing catalogues, generalized materials, many years of research, and the use of modern software analysis, the changes of static and dynamic pressure of mud volcanoes located in Shamakhi-Gobustan and Absheron areas before and after the strong Caspian (Baku) earthquake on November 25th, 2000 was researched. The seismic zonation has been done in a seismically dangerous territory of Baku with the consideration of ground conditions and macroseismic parameters of earthquakes scenario. The possibility of obtaining records of synthesized accelerograms for typical reference soils at maximum possible earthquake of magnitude M = 6.5 was done. The method of assessment of influence of soil conditions on the microseismic noise was also applied in the following work. The instrumental step-bystep measurement of Baku territory was carried out for the first time, the amplitude-frequency characteristics of the first kilometers of ground was also defined. The features of communication between the microseismic noise and the influence of soil conditions were examined. The increment of seismic intensity, and a map of seismic microzoning of Baku territory through instrumental seismic investigation using Nakamura’s technique (the spectral ratio between the horizontal and vertical components) was measured. The following thesis also has the combination of empirical and instrumental approach, the formation of models parameters of strong ground motion (acceleration, velocity and soil displacement), the comparative analysis of the results to effectively address the seismic hazard assessment for Baku megapolis and strong ground motion evaluation. The received results are of practical importance for the development of effective measures in order to minimize the damage from future large earthquakes, to ensure sustainable development of economy and societies of country.