Himachal Pradesh state is located in seismically active western Himalayas (India) and its seven districts are in seismic zone V and other in zone IV as per the seismic code of India. Ninety% area of Hamirpur district, the studied area, lies in zone V. Peak ground acceleration (PGA) is one of the most important seismic response parameters in structural seismic design, largely influenced by the sub-soil and input seismic motion characteristics. In the present work, the primary objective is to identify the areas in the district that are prone to amplification of peak ground acceleration and can be delineated for infrastructural planning. Peak ground acceleration is one of the most important parameters used in seismic design of the structures. It is estimated using the computer programme ProShake, wherein the soil parameters from 181 borehole profiles up to 30 m depth and software in-built standard earthquake input motions of magnitude 6.9, 7.0, and 7.2 used as the input parameters. The output peak ground acceleration range from 0.24 g to 0.72 g at the ground surface and from 0.21 g to 0.54 g at a depth of 10 m. There is an attenuation of peak ground acceleration at 30 m depth. The estimation of peak ground acceleration will play an important role in delineating the starta having higher peak ground acceleration amplification. This information can be effectively used for planning of important infrastructure projects like hospitals, educational institutions, and commercial establishments in an economical way in the studied area.

The main objective of this study is to present new method on the basis of genetic algorithms for attenuation relationship determination of horizontal peak ground acceleration and spectral acceleration. The proposed method employs the optimization capabilities of genetic algorithm to determine the coefficients of attenuation relationships of peak ground and spectral accelerations. This method has been applied to 361 Iranian earthquake records with magnitudes between 4.5 and 7.4 obtained from two seismic zones, namely Zagros and Alborz-Central Iran. The obtained results indicated that the proposed method can be characterized as a powerful tool for prediction horizontal peak ground and spectral accelerations.

One of the main issues in drainage watersheds is erosion and sediment yield. Lack of proper management in this field can be environmental hazards and even a threat to human life. The purpose of this study is fingerprinting the sources of sediment yield in sub-basins 1 and 2 of Talar drainage basin in Mazandaran province.140 soil samples in first approach and 80 samples in second approach collected respectively sub-basin 1 (77) and (47), sub-basin 2 (63) and (33) of lithological units and range of peak ground acceleration and 20 drape sediment samples at the outlet sub-basins and 28 geochemical elements measured as tracers in the samples. Using the Kruskal-Wallis test and discriminant function analysis, the composite fingerprints was determined. The largest relative contribution of sediment yield based on the Bayesian un-mixing model is in the first approach (sub-basin 1 unit sandstone and conglomerate with 59.1%, sub-basin 2 unit marl and shale with 47.2%), in the second approach (sub-basin 1 unit the range of peak ground acceleration at the level (0.51-0.6) g with 50.3%, and sub basin 2 units channel bank with 64.6%). The results of this study showed that the range of peak ground acceleration have a direct effect on control of sediment yield and erosion processes. Also, division of lithological groups as sources sediment yield based on range of peak ground acceleration, which have a great impact on sediment yield, as a new approach, can be of great help in understanding sediment yield processes.

Performance-based seismic design is a relatively new concept in structural engineering and earthquake engineering and is rapidly becoming widely accepted in professional practice. The basic idea of performance-based design is to design a structure so that it will “perform” in a specified manner when subjected to various earthquake levels. Therefore this design method involves a set of procedures by which a building structure is designed in a controlled manner such that its behaviour is ensured at predefined performance levels under earthquake loading. A nonlinear analysis tool is required to evaluate earthquake demands at the various performance levels. Pushover analysis is widely adopted as the primary tool for such nonlinear analysis because of its simplicity compared with dynamic procedures. The essential feature of conventional static pushover analysis is that it is a nonlinear procedure in which monotonically increasing lateral loads along with constant gravity loads are applied to a framework until a control node (usually referred to the building roof) sways to a predefined ‘target’ lateral displacement, or to a 'target' base shear, which corresponds to a performance level. The target displacement is the maximum roof displacement likely to be experienced during the design earthquake. Different performance levels have different target displacements, which represent different seismic intensities. The accurate estimation of target displacement associated with specific performance objective affect the accuracy of seismic demand predictions of pushover analysis. The target displacement for a multi degree of freedom (MDOF) system is usually estimated as the displacement demand for the corresponding equivalent single degree of freedom (SDOF) system.
The accuracy of approximate procedures utilized to estimate target displacement depend on the ground motion characteristics such as peak ground acceleration (PGA), peak ground velocities (PGV), acceleration response spectra (Sa) and pseudo velocity response spectra (Sv). Observing the damages of buildings after past earthquakes showed that the damage potential has a little dependence to maximum value of a single parameter such as ground acceleration or the total event duration. In the conventional methods, peak ground acceleration, as a parameter of the earthquake event, is directly/or indirectly used for force-based design and performance-based design. Peak ground motions, duration of strong motions and frequency content are important characteristics of earthquakes that have considerable effect on the earthquake damages. Main objective of the present research is to study the relationship between seismic parameters in the frequency-domain and peak ground acceleration, and the target displacement of the structure. For this purpose, the correlation coefficient between the seismic parameters and the target displacement is calculated and then the relationship between the target displacement and seismic parameters is evaluated based on it. The achieved results show that peak ground acceleration has weak correlation with the target displacement in comparison to the other parameters; whereas frequency domain parameters have more correlation with the target displacement.

In this study, the relationship between different definitions of duration with peak ground acceleration, focal depth, and soil conditions of the site using accelerometer records in Iran was calculated and presented. Then, 1054 three-component records of 197 seismic events recorded with a moment magnitude greater than or equal to 5.0 were used. All data for this study were obtained from the Road, Housing, and Urban Development Research Center (BHRC) in Iran. All records were for sites with focal depths and shear wave velocities within the first 30 m of depth. After preparing the records, the baseline correction was performed on them using Fortran programming and durations with g0.05 acceleration thresholds, uniform durations with g0.05 acceleration thresholds, significant durations 5-95% were calculated. Then, according to the Iranian 2800 earthquake code, soil type was grouped and the data were classified into three categories according to soil type. The data with soil group 4 were very low and unreliable. The results showed that with increasing peak ground acceleration, bracketed and uniform duration increased, while for significant durations, records with high significant durations generally have minor peak acceleration. Mathematical relationships were also shown for variations in any durations with peak ground acceleration and focal depth and soil type variations. Also, with softer soil, the slope of the bracketed and uniform duration relationship with PGA increased. Increasing the focal depth decreased the durability with different definitions. After a focal depth of 20 km, a threshold of 0.05g is usually less than 10 seconds. The relationship between shear wave velocity at 30 m depth and significant duration indicated that with increasing shear wave velocity, significant duration decreased. The relationship between the duration and maximum amplitude of earthquake ground motions was important for the seismic design of structures, especially reinforced concrete structures, which suffered from stiffness and reduced strength in successive earthquake cycles.

This study aims to investigate the analytical scheme of both the bi-normalized acceleration response spectrum and the bi-normalized tripartite response spectrum according to an ensemble of near-field strong ground motion records in the forward directivity conditions. For this purpose, the horizontal components of the ground acceleration time history were considered and a group of 16 ground motion pairs were selected, which have been recorded during two great earthquakes occurred in California, namely the Northridge (1994) and the Imperial Valley (1979). Also, the analytical scheme of the normalized acceleration response spectrum and the normalized tripartite response spectrum corresponding to a symbolic single-degree-of-freedom system have been compared with the related bi-normalized acceleration response spectra. It should be noted that the identification of near-field strong ground motion records is usually recognized by their physical characteristics such as peak ground acceleration (PGA), peak ground velocity (PGV), and the relatively short period process of energy release. Many strong ground motions have been recorded in less than 20 km from the fault rupture surface during intensive powerful earthquakes. In this case, the most famous earthquake tremors are the Imperial Valley (1979), Loma Prieta (1989), Landers (1992), and Northridge (1994) in California, plus the Kobe (1995) in Japan, Erzincan (1992), as well as Kocaeli (1999) in Turkey. Moreover, there are two very strong records, which were related to the Tabas (1978) and Bam (2003) earthquakes in Iran. The ensemble of the selected earthquake records in this research includes near-field ones that contain various tectonic occurrences. The main physical characteristics of the chosen records cover a wide range of the frequency content and strong ground motions duration as well as various high seismological amplitudes. The related values of the peak ground acceleration and velocity are numerically high. Generally, the peak ground velocity (PGV) is often viewed as a better indicator of the earthquake record damage potential than the peak ground acceleration (PGA). The large velocity pulses evident in the related plots can be viewed as damaging features. Moreover, the earthquake record damage potential also depends on how much dynamic ground displacement occurs during these velocity pulses. Referred to apparent physical influences caused by strong faulting mechanisms, the presence of high-amplitude velocity pulses is one of the most important characteristics of near-field records, which can be registered in a time-history domain. In general, these pulses appear as wave-shaped features with high amplitudes and long periods, which have a compound and continuous shape. Distinct powerful velocity pulses are resulted corresponding to high-amplitude acceleration pulses and spikes usually with a less than 1.5 second time-domain and also high-amplitude and short-time spikes with 0.2 to 0.3 second time-step in the spectral windows of the horizontal parallel and perpendicular components with respect to the fault rupture couture. These processes would essentially cause an enormous amount of the kinetic energy of strong ground motions to get released in the time-range of compound coherent and long-term velocity pulses in the related time history. In order to investigate these effects on the configuration of the aimed response spectrum, the velocity pulse time step, the ratio of corresponding kinematic energy of both two horizontal components, peak ground acceleration (PGA), and peak ground velocity (PGV) were considered.According to the performed computational assessments in this research, it was resulted that the bi-normalized response spectrum by the basic criterion of predominant period has a monotonous configuration and would get fewer effects due to variation of the notified spectral parameters.

In this paper, the peak ground acceleration (PGA) over the bedrock is calculated by a probabilistic and deterministic seismic hazard assessment. An active fault map of the region is prepared. For this purpose, all active faults in a radius of 100 km from Amol city center are recognized and their seismic and rapture parameters are determined. Afterwards, for seismic hazard analysis, the seismic parameters of study region are determined and seismic classification zone is performed. Maximum earthquake, seismic parameters and also occurrence rate are determined. Seismic hazard analysis is performed using 3 different attenuation relationships resulted in seismic hazard curves for Amol city center. The peak ground acceleration (PGA) for design levels MCE, OBE and benefit life structure 50 and 100 years are presented. For the PGA quantity design levels operating base earthquake (OBE), maximum credible earthquake (MCE) for horizontal and vertical dimensions were equal to sequences of 0.33, 0.5 and 0.3, 0.53 g, respectively.

The importance of non-structural components in seismic Performance Based Design of buildings is well known nowadays. In this research calculation of absolute acceleration applied on non-structural components located on floors of moment-resisting، eccentric braced and concentric braced frames subjected to earthquake ground motions has been studied. The results of nonlinear time-history analyses of 3، 5 and 7-story steel frames with 8 different periods and 5 reduction factors subject to 15 records of near-field earthquakes and 15 records of far-field earthquakes has been used to investigate the effects of different parameters on absolute acceleration induced in each floor of the structures. The effect of inelastic behavior of system، natural periods of primary and secondary systems، structural system type and near-field ground motions have been studied with use of modified shear-building models of steel frames. The shear building models are set to have an equivalent lateral force-deformation behavior in each story to the one’s of given steel frames. Reliability of these models to estimate the maximum roof displacement and the maximum inter-story drift of steel frames has been investigated elsewhere through probabilistic analysis of the results obtained from comprehensive incremental dynamic analyses. The relationships that are presented in building codes to calculate the force applied on non-structural components has been usually expressed as a ratio of peak ground acceleration. This method of calculating of input acceleration to non-structural elements ignores the effect of frequency content of design ground motion. The results of the present study have been used to introduce a new method for calculation the force applied on non-structural components based on ground acceleration spectrum. In this method the input acceleration to non-structural components has been expressed as a ratio of earthquake response spectrum (instead of the peak ground acceleration). For this ratio which is entitled as “spectral amplification factor” two different expressions have been proposed for use in structures with linear and nonlinear behavior. This approach explicitly accounts for the frequency content of design earthquake in calculation of peak floor acceleration. The results of this study show that Euro-code 8 and ASCE 7-2010 recommendations need to modify specially for the precise location of the non-structural element and inelastic behavior of the structure. It has been demonstrated that structural system type does not significantly affect the amount of induced acceleration on each floor of steel frames.

Peak ground acceleration is one of the most important factors that needs to be investigated in order to predict the devastation potential resulting from earthquakes in reconstruction sites. Besides, the maximum level of shaking control is subjected criteria that can be worth considering. In this research, a training algorithm based on gradient descent and Levenberg-Marquart (Train LM) were developed and employed by using strong ground motion records. The Artificial Neural Networks (ANN) algorithm indicated that the fitting between the predicted PGA values by the networks and the observed PGA values were able to yield high correlation coefficients of 0.78 for PGA.
From a deterministic point of view, the determination of the strongest level of shaking that is expected at a site has long been a significant consideration in earthquake engineering. Besides, knowledge of the maximum physically possible ground motions allows a meaningful truncation of the distribution of ground motion residuals, and as a result, leads to falling of the values computed in probabilistic seismic hazard analysis (Strasser and Bommer, 2009).
The peak ground acceleration parameter is often estimated by the attenuation of relationships and by using regression analysis. PGA is one of the most important parameters, often analyzed in studies related to damages caused by earthquakes (Gullo and Ercelebi, 2007). It is mostly estimated by the attenuation of equations and is developed by a regression analysis of powerful motion data.
Kerh and Chaw (2002) used software calculation techniques to remove the lack of certainties in declining relations. They used the mixed gradient training algorithm of Fletcher-Reeves’ back propagation error (Fletcher and Reeves, 1964). They applied three neural network models with different inputs including epicentric distance, focal depth and magnitude of the earthquakes. These records were trained and then the output results were compared with available nonlinear regression analysis.
In this article, to estimate strong ground motion acceleration component in an area, four artificial neural networks with different algorithms were used, including General Regression Neural Network (GRNN), Nonlinear Auto Regression neural network (NARX), Feed-Forward Back-Propagation error (FFBP) and General Feed-Forward Neural Network (GFFNN). Input vectors of neural networks include four parameters, which have key effects in occurrence of an earthquake in an area. The parameters include magnitude of moment, rupture distance of earthquake center, mechanism of faults, and ranking of site. Output vector has only one component: maximum peak ground acceleration for an earthquake in an area is used as a target output.
After different tests, GRNN network has maximum output correlation coefficient (0.87) and General Feed-forward Back-Propagation error neural network (FFBP) has the least (0.41). Besides, GRNN network had the least mean square error (0/014), and Back-Propagation network had 0.125. In this research, GRNN neural network is the best neural network, which can estimate possible peak acceleration more than 1g in an area.
Artificial neural networks are a set of non-linear optimizer methods which do not need certain mathematical models in order to solve problems. In regression analysis, PGA is calculated as a function of earthquake magnitude, distance from the source of the earthquake to the site under study, local condition of the site and other characteristics that are linked to the earthquake source such as slippery length and reverse, normal or wave propagation. In non-linear regression methods, non-linear relations that exist between input and output parameters are expressed as estimations, through statistical calculations within a specified relationship (Douglas, 2003).

To improve the design of surface structures built on underground structures for safety and earthquake resistance, it is necessary to study the effects of the underground structures on wave propagation scattering and surface ground acceleration. To this end, various parameters must be studied, including input motion, structure embedment, and dimensions of different subway stations. The present study focuses on these parameters by employing a nonlinear cyclic model called ARCS soil's shear modulus reduction and damping ratio increase corresponding to those given by the user. The variations in spectral ratio, affected period range, peak ground acceleration, and peak relative lateral displacement versus relative distance under near-fault and far-fault earthquakes are presented. The results indicate that different amplification or de-amplification effects at different surface positions were produced at each frequency by appearing a significant influence on the dynamic behavior of ground surface, soil layers, and the surface structure when a subway station is present. A 1.3 times increase in the surface ground acceleration when subjected to far-fault earthquakes and a 1.6 times increase in the relative displacement indicated that study parameters have significant influence on the amplification ratio and scattering of wave.