Complex of general seismic zoning maps OSR-2017 of Uzbekistan

Abstract

The quantitative assessment of seismic hazard of Uzbekistan has been examined, and new maps of seismic zoning has been developed. Quasihomogeneous seismological areas and seism-generating zones are considered as seismic sources, based on the analysis of seismotectonic data. The seismological parametrization of seismic sources has been carried out, including determination of parameters of earthquake's reoccurrence for different power levels, seismic potential and a predominant type motion in the source of occurring earthquakes. The reoccurrence parameters of seismic sources were both determined by directly from Gutenberg–Richter dependence law and using summation and distribution methods. Setting were conducted separately for a sample of strong (M ≥ 5) and weak (М < 5) earthquakes. The seismic potential Mmax of seismic active zones was determined by seismological and seismotectonic methods. The predominant type of movement in the faulting for each seismic source is reverse fault. Regional regularities of seismic intensity attenuation with distance of different power levels are determined. The seismic hazard is expressed in points of a macro seismic scale, in velocities and accelerations of ground motions, and it is characterized by calculated seismic intensity with the set probability (Р = 0.9, Р = 0.95, Р = 0.98 and Р = 0.99) not exceed within 50 years in the constructed maps. In seismic zoning map, the seismic intensity was in average soil conditions. The developed complex of maps considers a number of uncertainties of the input parameters in relation to both incompleteness of initial seismological and seismotectonic data, as well the probabilistic nature of seismic process and seismic intensity. The factors of uncertainty of the input parameters are taken into account by constructing a logic tree. The constructed maps of the general seismic zoning are intended for implementing antiseismic actions in Uzbekistan.

Keywords

• Seismic hazard
• Seismic zoning
• Seismic sources
• Seismic activity
• Seismic potential
• Seismic load intensity attenuation laws