Microtremor measurements are a widely recognized and effective method for evaluating the dynamic properties and potential seismic vulnerability of buildings. These measurements allow for the determination of critical parameters such as the dominant frequency, amplification factor, vulnerability index, and floor spectral ratio (FSR) for each floor of the building under investigation. In this study, microtremor measurements were conducted on a 26-storey monolithic reinforced concrete residential building located in the heart of Tashkent city. Recordings were made using six velocimeters simultaneously for 30 minutes. Measurements were taken on the basement floors (two floors), on the first floor, and then at two-floor intervals throughout the entire height of the building. Additionally, free-field measurements were taken on the ground outside the building to serve as a reference. The data was analyzed using GEOPSY software, which generated HVSR (Horizontal-to-Vertical Spectral Ratio) curves for the structure. The analysis showed that the building has the appropriate characteristics to effectively absorb seismic impact, indicating that it is well-constructed and capable of withstanding seismic forces. The strong structural integrity, demonstrated through low amplification and vulnerability indices, suggests that the building's design provides adequate protection against potential earthquake damage. These findings contribute to the broader understanding of how microtremor studies can be applied in the seismic evaluation of tall buildings in urban conditions.

Keywords: microtremor, natural frequency, FSR, HVSR, vulnerability index, resonance

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