THE SEISMIC EVENT ON JANUARY 23, 2024 AND THE ANALYSIS OF THE CONSEQUENCES FOR THE BUILDINGS OF THE ALMATY

Abstract

On January 23, 2024, an earthquake of magnitude M_b =7.27 occurred in China. In Almaty city, it was registered by stations of the engineering and seismometric service of “KazRDICA” JSC and seismic stations of the National Scientific Center for Seismological Observations and Research. What is new is the analysis of instrumental data from seismic stations and the consequences for city buildings based on the results of sample surveys of 188 construction sites. It is established that the intensity of the seismic impact is not less than 5 points. There is no discernible effect of the presence of tectonic faults on the instrumental characteristics of seismic motion in the basement of the building (stations No. 17 ‘Novaya Ploshchad’ and No. 16 ‘Hotel’). At Station No. 3 “School”, abnormally high acceleration values of 88.46 cm/s² and 81.89 cm/s² were recorded at floor level. It was found that the horizontal components of the seismic response have a significant long-period component. There is a peak in the spectral curve at a period of approximately 0.9-1.0 seconds. Even with such an intensity of impact, non-load-bearing structural elements of the building were damaged, which leads to the need to incur financial costs for cosmetic repairs of buildings. An algorithm for carrying out repair and restoration work is presented. It has been established that this type of seismic impact poses a risk to high-rise buildings. Consequently, the earthquake was felt by residents of high-rise and multi-storey buildings. A detailed survey is recommended for a number of buildings, which entails additional costs. The results of the work are useful for understanding ways to solve the problems of earthquake-resistant construction using the results of an analysis of the effects of local earthquakes. It is shown that even with 5-6 magnitude earthquakes, the damage can be significant.