Problems of Engineering Seismology: article

Аnnotation: Comparison of seismic hazard assessments of the We carried out comparison of seismic hazard assessments of the territory obtained with the same input parameters was carried out, but using different methodological approaches – the approach of Yu.V. Riznichenko based on the theory of macroseismic and spectral-time shaking and the classical Cornell probabilistic approach based on the full probability theorem. As models of seismic sources, linearly extended sources (seismogenic zones) and area sources (quasi-uniform seismological provinces) were considered. We used a number of authors’ attenuation dependences, established on the basis of analysis of isoseismic earthquake patterns in Central Asia, when assessing the seismic hazard of the study area in terms of macroseismic intensity, along with the dependence of N.V. Shebalin, obtained from the world data (I = 1.5M–3.5lgR+3). To estimate seismic hazard in engineering seismic indicators, the dependencies built into the R-CRISIS software package, developed over the past 10–12 years for shallow active crust and stable regions, were used as the equation of ground motions. For probability Р = 0.90 not exceeding the level of seismic impacts during 50 years, the maximum differences in seismic hazard assessments when applying the two approaches under consideration for the whole seismic-active part of the study area are ∆I = 0.39 points, for probability Р = 0.95 – ∆I = 0.54 points, for probability Р = 0.98 – ∆I = 0.61 points and for probability Р = 0.99 – ∆I = 0.76 points. A similar comparison of seismic hazard assessments in the values of the maximum accelerations of ground vibration leads to the following figures: with Р = 0.90 ∆amax = 75 cm/s2; with Р = 0.95 ∆amax = 111 cm/s2; with Р = 0.98 ∆amax = 167 cm/s2; with Р = 0.99 ∆amax = 273 cm/s2.