Problems of Engineering Seismology: article

Аnnotation: The first stage of the seismic treatment assessment for earthquake engineering design is seismic hazard assessment. For this purpose during seismological and seismotectonic researches the sesmogeneric structures are selected. Then, the maximal credible magnitudes, the corresponding recurrence periods, the faulting types, the distances between the selected faults and the construction sites, the ground types at the site are investigated. And at last it is necessary to assess the acceleration amplitudes decay - to investigate the attenuation acceleration regularities. In this article various techniques for assessment of acceleration attenuation with distance in the epicentral zones of earthquakes are considered. It’s shown that the empirical estimations of mean values of the amplitudes for various distances yield the highest accuracy. Any a priori given expressions for attenuation curves aren't applied. At the Institute of Physics of the Earth (IPE), Moscow, using the world-wide strong ground motion database, it is shown, that in the engineering range of accelerations, the zones differing with attenuation and dependences on the source mechanism and ground conditions are identified. Each zone has the own attenuation equation with the corresponding standard deviation. Such methodic of acceleration attenuation assessment is applied for Garhwal region, Himalayas Seismic Belt. The near-field strong ground motion records registered in the near fields of the recent strong earthquakes in the western part of the Himalayas. Strong motion records of the 1986 Dharamsala ( M