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A probabilistically based hazard map of Albania expressed in terms of PGA for 475 years of return period following the spatially smoothed seismicity approach proposed by Frankel (1995) and developed by Slovenian researchers (Lapajne et al. 1997), is presented.  Taking advantage of this development, an effort has been made to analyze the parameters of site-dependent acceleration response spectra parameters of the current seismic design code KTP-N.2-89 in Albania.

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In this article, stochastic finite-fault simulation combined with site response analysis is used to understand the spatial distribution of ground motion in Guwahati city due to three damaging earthquakes. The rock level ground motion for the scenario earthquakes is generated based on the stochastic finite-fault methodology. These simulated motions are further amplified up to the surface by equivalent linear site response analyses using the available borelog data at 100 different locations in Guwahati city. A set of twenty simulated rock level time histories for each event, are used to compute the surface level ground motion. Response spectra are computed and the results are presented in the form of contour maps, at selected natural periods. The mean amplification due to local soil deposit is as high as 2.2 at most of the sites in Guwahati city. Based on these simulated motions, an average site correction factor is obtained for soil sites in Guwahati city. The standard error in the simulated response spectra is also reported. The contour maps obtained will be useful in identifying vulnerable places in Guwahati city.

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Application of local conditions in earthquake engineering is interconnected with the achievements in natural sciences like geology, seismology and geotechnics. Due to variation of soil conditions on the territory of Slovakia, the properties of response spectra and/or simulated or adapted recorded accelerograms should take these phenomena into account. The paper discusses the approaches to the determination of shear wave velocities and soil-structure interaction. Possible application of latest records from new Slovak seismic station network is discussed, too.

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The capital of Bulgaria, Sofia is a growing city with population around 1.22 million. The city is exposed to a high seismic risk since it is placed in the centre of Sofia seismic area. Over the centuries in the town of Sofia the macroseismic intensities have been larger than IX (MSK). A study of the site effects and the microzonation of a part of metropolitan Sofia, based on a  modelling of seismic ground motion along three cross sections are presented. Realistic synthetic strong motion waveforms have been computed for an expected scenario earthquake (M=7) applying a hybrid modelling method, based  on the modal summation technique and finite differences scheme. The site amplification is determined in terms of response spectra ratio (RSR). A set of time histories and quantities of earthquake engineering interest are supplied, that allow the definition of six zones characterized by specific response spectra. The results from this study constitute a “database” that describes the ground shaking of the urban area.  The synthetic velocigrams are employed to calculate the distribution of the horizontal strain factor Log10e using a simplified relation between particle velocity and velocity of shear waves in the surface layer. It is shown  that it is possible to estimate liquefaction susceptibility in terms of standard penetration tests (SPT), Nvalues and initial over burden stress. Using the data for maximum particle velocity and empirical relationships developed from the Northridge earthquake, 1994 the distributions of the expected pipe breaks and red-tagged buildings for Sofia city are shown.

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The city of Sofia has the densest population of Bulgaria — around 1.27 million people. The capital is exposed to high seismic risk. According to the Bulgarian seismic code, Sofia has been included in a seismic category characterized by intensity IX (MSK), which corresponds to a horizontal acceleration of 0.27 g for the anchoring of the elastic response spectrum. Because of the lack of instrumental seismic data, realistic synthetic strong motion waveforms for two opposite positions of seismic sources, have been generated for an expected earthquake scenarios ( M = 7) along three geological profiles. A hybrid modeling method has been used for the modeling, which is based on the modal summation technique and finite difference scheme. The calculation has been done using an extended source model. The site effect is represented in terms of response spectra ratio (RSR), with respect to a bedrock model. The three components synthetic seismograms, computed in the domain of displacement, velocity and acceleration have been processed to extract some parameters very useful for engineering applications.

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The study area lies in south Egypt on the west bank of the River Nile about 12 km north to the Aswan City. The aim of the present study is a trial to investigate subsurface structure conditions, to determine the dynamic characteristics of the subsurface rocks and to study the effect of the near earthquake activities on the proposed location of Aswan New City. In this study nineteen seismic refraction P- and S-waves profiles were conducted. The output results include velocities of P-and S-wave and the thickness of each layer. The bulk density of soil layers was calculated from determined P-wave values.  The measured shear wave velocity and bulk density for each layer were used to compute the maximum shear modulus. These parameters for each layer are used as input data to compute the responses of horizontally layered soil profiles subjected to bedrock input motion from strong earthquake using EERA program. The obtained response values of soil layers are represented by the surface acceleration, from which response spectra with damping ratio of 5 % are obtained, surface Fourier amplitude spectra, amplification ratio between rock outcrop and free surface, and the shear stresses and strains characteristics at the sublayer No. 2 in all selected profiles sites. The output of this study is very important for solving the problems, which associated with the construction of various civil engineering purposes and for earthquake resistance structure design.

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The study area lies in south Egypt on the west bank of the River Nile about 12 km north to the Aswan City. The aim of the present study is a trial to investigate subsurface structure conditions, to determine the dynamic characteristics of the subsurface rocks and to study the effect of the near earthquake activities on the proposed location of Aswan New City. In this study nineteen seismic refraction P- and S-waves profiles were conducted. The output results include velocities of P-and S-wave and the thickness of each layer. The bulk density of soil layers was calculated from determined P-wave values.  The measured shear wave velocity and bulk density for each layer were used to compute the maximum shear modulus. These parameters for each layer are used as input data to compute the responses of horizontally layered soil profiles subjected to bedrock input motion from strong earthquake using EERA program. The obtained response values of soil layers are represented by the surface acceleration, from which response spectra with damping ratio of 5 % are obtained, surface Fourier amplitude spectra, amplification ratio between rock outcrop and free surface, and the shear stresses and strains characteristics at the sublayer No. 2 in all selected profiles sites. The output of this study is very important for solving the problems, which associated with the construction of various civil engineering purposes and for earthquake resistance structure design.

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The aim of our study is to determine the design ground acceleration values at the whole territory of Debrecen and to accomplish the seismic risk map of Debrecen using synthetic seismograms. Synthetic seismograms are computed by the so called ``hybrid technique" along 11 different profiles crossing the city. The hybrid technique consists of the modal summation method, followed by finite difference modelling. 11 independent computations have been performed using the same seismic source but different profiles. The seismic source has been located in the so called “Mobile Zone”, which is a seismically active fault system in Érmellék region. The focal mechanism and the homogeneous and heterogeneous parts of the profiles are  known from geophysical and geological data of the investigated area. As the results of the computations PGA grid maps of Debrecen for the 3 different components and the spectral  acceleration (response spectra, SA) charts of the synthetic seismograms for the transversal components came  into existence. The seismic risk map of the city has been completed from the SA charts created from the synthetic seismograms and from the grid map of the buildings in Debrecen with different number of floors by applying GIS tools.

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The aim of our study is to determine the design ground acceleration values at different parts of Debrecen along two profiles crossing the city. Synthetic seismograms are computed by the so called “hybrid technique”. This technique consists of the modal summation method, followed by finite difference modelling. Two independent computations have been performed using two different seismic sources and profiles. In both computations the seismic sources have been located in the so called “Mobile Zone”. The Mobile Zone is a seismically active fault system between the villages of Hosszúpályi and Gálospetri. The focal mechanism and the homogeneous and heterogeneous parts of the profile are known from geophysical and geological data of the investigated area. The maximum response spectra ratio values of the horizontal component are found below 1 Hz all along the profile and the frequencies below 1 Hz are in good agreement with the natural frequencies of the multi-storeyed buildings. Computed effective peak acceleration (EPA) values are found to be in good agreement also with the higher than 6° MSK macroseismic intensity values estimated from the assessment records of damages wrought by the 1834 Érmellék earthquake.

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prescribed response spectra, Research Report R76-4 . Massachusetts Institute of Technology, Department of Civil Engineering, Cambridge, Massachusetts, 1976. Vanmarcke E. H

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