Preliminary Estimates of the Characteristics of Radiation and Propagation of Seismic Waves and the Ground Motion Prediction Equations for the Ural Region

This paper reports the first estimates of the characteristics of radiation and propagation of seismic waves in the Ural region obtained by modeling the accelerograms of recorded local earthquakes. The obtained source parameters are similar to those of the Caucasian region, while the seismic wave propagation characteristics are similar to those of the Baikal rift zone. A somewhat increased duration of strong motion in the Ural region can obviously be explained by a fractured structure of the Ural Mountains. The ground motion prediction equations (GMPEs) proposed by the Global Earthquake Model (GEM) project for the Ural region correspond to the platform regions with a stable continental seismicity, while the obtained characteristics of radiation and propagation of seismic waves in the Ural region correspond to the seismically active regions with a crustal seismicity. The comparison of the amplitudes of acceleration response spectra of the strongest earthquake recorded in the region with the estimates obtained by using the GMPEs has revealed a considerable excess of the estimates over the observed spectral amplitudes. Hence, the recommendations of the GEM should not be used in their original form, without correction factors, and it is necessary to develop the regional GMPEs for the purposes of seismic hazard analysis.