Detailed seismic zoning maps of the Turkestan region of Kazakhstan

Owing to Kazakhstan’s transition to new construction standards that align with Eurocode 8, detailed seismic zoning (DSZ) maps of the country are necessary to assess seismic hazards using modern methods. The seismic hazard in construction zones is determined using seismic zoning maps with varying levels of detail. The methodology applied to obtain the DSZ maps was consistent with that used to develop the first probabilistic general seismic zoning maps of Kazakhstan, which were included in the 2017 building regulations for seismic zones and conformed to the Eurocodes. This study met the requirements of the DSZ project and included new data and analytical tools. In addition, the seismic databases and source models were updated. The seismic hazard assessments performed in this study included seismic sources and attenuation modeling, ground motion calculations, and determining the probability of motion exceeding the peak ground acceleration within 50 a, which yielded DSZ maps for the Turkestan region of Kazakhstan. On maps showing a 10% probability of exceedance within 50 a, the obtained values ranged from 0.020 g to 0.370 g, whereas for a 2% probability of exceedance in 50 a, the values ranged from 0.052 g to 0.720 g. The maximum predicted ground acceleration values were located in the southeastern part of Turkestan region within a high-seismicity zone containing active faults. The maps produced in this study facilitate assessments of the probability of destructive earthquakes in the region, thereby enabling the development of risk-reduction and mitigation strategies. The maps also serve as a basis for updating previous building codes.