Seismic site response analysis is required to determine the response of ground and estimating the free field response spectra for future design purposes. The seismic site response analysis is generally performed in a deterministic way. The uncertainties of the parameters used to develop the subsoil model are high and hence, the execution of a deterministic analysis of the seismic amplification does not properly represent the response of a site. In the present study, a detailed stochastic method with uncertainty modelling for 1D site response analysis is proposed. Monte Carlo simulation is effectively used to model the various uncertainties in input parameters. The uncertainties in input ground motion, shear wave velocity, layer thickness and non-linear soil properties are modelled in the analyses. Stochastic 1D seismic site response analysis is attempted in the present study and parametric study has been performed. The proposed methodology is then used effectively to carry out the parametric study to investigate the sensitivity and uncertainty of parameters used in the seismic site response analysis. The influence of input ground motion, uncertainty in shear wave velocity, uncertainty in shear modulus reduction curve and damping curve has been checked in the present study. Rigorous analyses on large number of profiles for each parameter have been carried out.

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In Osaka, Uemachi Fault is one of the famous active faults. It across the center of Osaka and lies in N–S direction mainly and is more than 40 km in length. These sediment are very thick layers over 1000m therefore, fault structure are appeared as flexure zone (only vending the strata) and hidden the fault displacement around the surface. Main Uemachi fault trace are distributed near Uemachi uphill and two spray fault (Suminoe and Sakuragawa) is distributed NE-SW. An average displacement rate of main fault is 0.4 m/ka (ka is kiro age before) (Headquarters for Earthquake Research Promotion, 20041)). However, because of modified by erosion and urban development, main fault (N-S direction) is difficult to estimate the displacement rate near the surface. In this study, we try to estimate the width of flexure zone using geotechnical borehole data. These spray faults does not make clear the distribution and also these length. Upper Pleistocene marine clay (Ma12) is a good indicator of the flexure zone. Ma12 marine clay layer is correlated to marine isotope stage 5e, therefore the marine clay bottom age is considered about 125ka. We constructed many cross sections in and around the fault zone and found that Ma12 marine clay layers were folded and were recognized on both the up and down sides of the flexure. The result of this study, the displacement rate of the flexure zone is 0.26 m/ka and distributed parallel to the main fault. It about 12km length and the Sakuragawa and Suminoe flexure are continuing and seemed to be the one of the main fault in the Uemachi fault system.

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To study the dynamic stability of the layers of clay and water-saturated sandstones with the position estimate of their liquefaction at seismic impacts, relevant project (forecast) seismic activity area, in the laboratory of the Department of bases, foundations, structural dynamics and engineering geology tests of soils equivalent to a force against seismic action triaxial cyclic loading. The results obtained were used to develop recommendations for the construction of basements and foundations for the effects of seismic loads on the mechanical properties of the soil base and, as a consequence of vibration liquefaction soil.

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One of the important characteristic of the liquefaction damage observed at Urayasu city during the Great East Japan Earthquake is that liquefied and non-liquefied site was inhomogeneously distributed. The difference in damage levels has often been explained by the presence/absence of past ground improvement and by the difference in the dates of reclamation work. Such causes of extensive damage are, no doubt, correct. However, sufficient explanations have not been provided yet concerning the mechanism of liquefaction occurrence in ground with large fine fraction content and the reason why the liquefaction damage was non-uniform. In this study, seismic response analysis with multi layered system was employed paying special attention to the stratum organization at the deeper part of the subsurface liquefiable layer. Analysis result showed that, in addition to characteristic of the earthquake motion and inhomogeneity of the ground itself, irregularly shaped stratum organization of Urayasu city was one of the important factor for extensive and non-uniform liquefaction damage.

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This report is devoted to one of topical questions of a seismic building - to specification of seismicity of a territory depending on concrete soil conditions of the building area. It is noticed that the method of seismo-districts widely applied now possesses suffer from grave shortcomings, in particular, with reference to concrete soil conditions. It in great degrees concerns a choice of the reference soil corresponding to seismicity of territory on a card of seismic zoning. For definition increment mark of seismicity on others soils concerning the reference the indicator of acoustic rigidity (product of density of a soil for speed of distribution of seismic waves) and position of level of subsoil waters is used. At such approach to the question decision all soils (except rock) give an identical increment mark, irrespective of their properties and conditions. As have shown results of numerous experimental researches, question decisions above-mentioned by practically in all cases yield the results far differing from observed phenomenon in the nature. It is based on that the indicator of acoustic rigidity not in all soils depends on their humidity (sand, gravel, rubble, rigid clay and rock). Humidity of a soil can be a matter only for clay soils in plastic conditions. Besides in the given approach to the question decision are not considered physic-mechanical and stability indicators of a concrete soil, in each special case providing its seismic stability. The proposed method offered by the author is deprived above mention lacks.

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The site-specific one-dimensional (1-D) ground response analysis of two ports in Mumbai, Jawaharlal Nehru port (JNPT) and Mumbai port; have been performed by using non-linear (time-domain) approach and compared with equivalent-linear (frequency domain) approach. The analysis utilizes site-specific bedrock level input motions developed by deaggregating the seismic hazard at the port sites. The outcome of the ground response analysis is presented through acceleration, strain and stress time-histories at ground surface, peak ground acceleration (PGA) profile along depth of soil deposit, peak spectral acceleration response spectrum and Fourier amplification spectrum. The comparison of the results from equivalent-linear and non-linear approaches in terms of free-field response spectrum and Fourier amplification spectrum shows that the response is nearly same for stiffer site however for soft site; it is overestimated by equivalent-linear analysis. The JNPT site is observed to have higher amplification potential in comparison to the Mumbai port site.

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The present report is devoted to questions of research of depth of compressed thickness as a result dilution water sated soils in the basis of constructions at seismic fluctuations. On the basis of conditions of limiting balance - at equality of the maximum tangents of seismic pressure and durability of a fluctuating soil authors offer the formula for definition depth diluted zone at the moment of influence of dynamic loading to a soil. According to researches of authors, seismic tangents of pressure, arising in thickness of a soil at passage of seismic waves, along with strong soil indicators, are one of the main reasons of occurrence dilution a soil in these conditions. The important factor also are forces of cohesion of the soil which increase always lead to reduction of a diluted zone as a result of increase of durability of the soil promoting increase of resistibility of a soil to influencing tangents to seismic pressure. The analysis of conditions origin of the dilution a soil depending on distinction of a kind of cohesion is given.

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