Tajik Academy of Sciences

Abstract: Within the framework of the EMCA - Earthquake Model Central Asia - project, the cities of Bishkek (Kyrgyzstan) and Dushanbe (Tajikistan) were selected for building monitoring using measurements of seismic noise to obtain the dynamical properties of the buildings. Eight buildings of different construction types, date of construction and building height, both, Soviet-era and recently constructed buildings, were instrumented for a period of a few hours. In this study, an overview of the experiment is given, including a short description of each monitored building’s structure and the performed installation. Preliminary results for a representative Soviet-era residential building in Dushanbe are presented. Modal analysis is performed using the Frequency Domain Decomposition (FDD) method to estimate the natural frequencies and the mode shapes. The wave propagation velocities in the two directions along the building axes are determined by an interferometric approach. Although the experimental set-up was not the optimal, valuable information about the dynamical characteristics of the buildings were still obtained.

Abstract: The Varzob Valley in the Central Tajikistan, due to its proximity to the Gissar mountains range, acts like a funnel for the air mass transported by the southern winds. For a better understanding this local phenomenon, the gross alpha and beta as well as 40K, 137Cs, 232Th and 238U activity concentrations together with the Th/U ratio were studied. The results showed the existence of a deposition process of the airborne dust on the southern slope of Gissar Mountains. The influence of the Odjuk pegmatite outcrop on the natural radioactivity along the Varzob valley was evidenced too. At the same time, no traces of radioactive contamination from local anthropogenic sources were found.