National Mitigation Strategy against Earthquakes in Central Asia

2020 ◽  
Author(s):  
Sung-Woo Moon ◽  
Farkhod Hakimov ◽  
Jong Kim ◽  
Klaus Reicherter ◽  
Hans-Balder Havenith ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Central Asia ◽  
Ground Motion ◽  
Urban Areas ◽  
Site Effects ◽  
Site Response ◽  
Engineering Properties ◽  
Response Analysis ◽  
Earthquake Scenarios ◽  
Geological Conditions

<p>Throughout history, earthquakes have caused extensive damages in urban areas with important infrastructures and high population density. Especially, earthquakes have extensively damaged many regions of Central Asia (e.g., Tashkent in 1966, and Almaty in 1911). Hence, the estimation of the seismic hazard of the urban areas in Central Asia is very important due to the high level of seismicity in Central Asia and the rapid construction of new buildings. The high earthquake-induced damages in the cities often result from the local geological conditions and engineering properties of the soils that can produce significant site effects. Such seismic effects combined with the high vulnerability of buildings can result in extreme disasters during earthquakes. Therefore, geotechnical engineers/seismologists should decide to divide the city into specific microzones depending on their site effects and soil properties. However, conventional approaches in Central Asia have been proposed, based on (1) general engineering geological information; (2) the building code based on the estimates of the ground motions in terms of MSK-64 scale developed in 1978; and (3) the quantitative assessment only mapping and overlaying the data.</p><p>By characterizing the soft layers of their nature, thickness, and structure, and assessing the numerical model developed for the high-seismicity area of Central Asia, we can better assess specific site effects in each region of Central Asia. In addition, to predict the essential consequences of earthquakes, physically-based ground motion simulations should be developed by numerical simulations considering all possible processes of seismic wave propagation. Compared to empirical ground-motion predictions, numerical simulations of earthquake scenarios will provide much more flexible and better-suited solutions for most applications – especially those involving complex city environments. The ground-motion prediction equations or stochastic ground-motion estimates integrate characteristics of the earthquake source, path, attenuation, and site effects via approximate or statistical approaches. This method will provide rapid solutions that may be valid for a well-known context and would also be applied in Central Asia, for comparison with the numerical simulations. Finally, the quantitative approach for microzoning map incorporated with numerical simulation/site response analysis, for infrastructures (e.g., buildings, bridges, and dams) will be significantly useful in the future.</p>

scholarly journals Does the One-Dimensional Assumption Hold for Site Response Analysis? A Study of Seismic Site Responses and Implication for Ground Motion Assessment Using KiK-Net Strong-Motion Data

2019 ◽  
Vol 35 (2) ◽  
pp. 883-905 ◽  
Author(s):  
Marco Pilz ◽  
Fabrice Cotton
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Site Response ◽  
Three Dimensional ◽  
Strong Motion ◽  
Site Response Analysis ◽  
Response Analysis ◽  
One Dimensional ◽  
Ground Motion Variability ◽  
The One

The one-dimensional (1-D) approach is still the dominant method to incorporate site effects in engineering applications. To bridge the 1-D to multidimensional site response analysis, we develop quantitative criteria and a reproducible method to identify KiK-net sites with significant deviations from 1-D behavior. We found that 158 out of 354 show two-dimensional (2-D) and three-dimensional (3-D) effects, extending the resonance toward shorter periods at which 2-D or 3-D site effects exceed those of the classic 1-D configurations and imposing an additional amplification to that caused by the impedance contrast alone. Such 2-D and 3-D effects go along with a large within-station ground motion variability. Remarkably, these effects are found to be more pronounced for small impedance contrasts. While it is hardly possible to identify common features in ground motion behavior for stations with similar topography typologies, it is not over-conservative to apply a safety factor to account for 2-D and 3-D site effects in ground motion modeling.

scholarly journals Summary of Research on Site Response Analysis

2021 ◽  
Vol 276 ◽  
pp. 02024
Author(s):  
Jing Cai ◽  
Jianqi Lu ◽  
Shanyou Li
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Reference Site ◽  
Site Response ◽  
Response Analysis ◽  
Observation Data ◽  
Empirical Methods ◽  
Theoretical Methods ◽  
Advantages And Disadvantages ◽  
Soil Site

A large number of seismic observation data and macroscopic survey of earthquake damage indicate that soil site may amplify the intensity of ground-motion and thus aggravate the damage to the structures on the soil site[1]. The influence of site response on ground motion is one of the most important topics in earthquake engineering. The methods of predicting the site effects can be divided into two groups with respect to theoretical methods and empirical methods. The theoretical methods of predicting site effects are to analyse the site response to ground motion based on the theory of seismic wave propagation in which the detailed soil information is required. Whereas the empirical methods predicting the site effects by empirical prediction model which is determined using observed seismic data or ground pulsation data. According to whether the reference site is introduced, the empirical methods can be further divided into the reference site method and the non-reference site method. This article introduces in detail the principles, advantages and disadvantages of various methods of analysing site effects, which is of reference value for further research on site ground motion response.

scholarly journals Investigating the influence of topographic irregularities and two-dimensional effects on surface ground motion intensity with one- and two-dimensional analyses

2014 ◽  
Vol 14 (7) ◽  
pp. 1773-1788 ◽  
Author(s):  
G. Ç. İnce ◽  
L. Yılmazoğlu
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Soil Conditions ◽  
Response Analysis ◽  
Two Dimensional ◽  
Ground Acceleration ◽  
Equivalent Linear ◽  
Local Soil ◽  
Different Depths ◽  
Earthquake Response Analysis

Abstract. In this work, the surface ground motion that occurs during an earthquake in ground sections having different topographic forms has been examined with one and two dynamic site response analyses. One-dimensional analyses were undertaken using the Equivalent-Linear Earthquake Response Analysis (EERA) program based on the equivalent linear analysis principle and the Deepsoil program which is able to make both equivalent linear and nonlinear analyses and two-dimensional analyses using the Plaxis 8.2 software. The viscous damping parameters used in the dynamic site response analyses undertaken with the Plaxis 8.2 software were obtained using the DeepSoil program. In the dynamic site response analyses, the synthetic acceleration over a 475-year return period representing the earthquakes in Istanbul was used as the basis of the bedrock ground motion. The peak ground acceleration obtained different depths of soils and acceleration spectrum values have been compared. The surface topography and layer boundaries in the 5-5' cross section which cuts across the study area west to east were selected in order to examine the effect of the land topography and layer boundaries on the analysis results, and were flattened and compared with the actual status. The analysis results showed that the characteristics of the surface ground motion change in relation to the varying local soil conditions and land topography.

Modeling nonlinear site effects in physics-based ground motion simulations of the 2010–2011 Canterbury earthquake sequence

2020 ◽  
Vol 36 (2) ◽  
pp. 856-879 ◽  
Author(s):  
Christopher A de la Torre ◽  
Brendon A Bradley ◽  
Robin L Lee
Keyword(s):  
Wave Propagation ◽  
Ground Motion ◽  
Site Effects ◽  
Ground Motions ◽  
Site Amplification ◽  
Earthquake Sequence ◽  
Response Analysis ◽  
Site Specific ◽  
Ground Motion Simulations ◽  
Empirical Ground

This study examines the performance of nonlinear total stress one-dimensional (1D) wave propagation site response analysis for modeling site effects in physics-based ground motion simulations of the 2010–2011 Canterbury, New Zealand earthquake sequence. This approach explicitly models three-dimensional (3D) ground motion phenomena at the regional scale, and detailed site effects at the local scale. The approach is compared with a more commonly used empirical VS30-based method of computing site amplification for simulated ground motions, as well as prediction via an empirical ground motion model. Site-specific ground response analysis is performed at 20 strong motion stations in Christchurch for 11 earthquakes with 4.7≤ MW≤7.1. When compared with the VS30-based approach, the wave propagation analysis reduces both overall model bias and uncertainty in site-to-site residuals at the fundamental period, and significantly reduces systematic residuals for soft or “atypical” sites that exhibit strong site amplification. The comparable performance in ground motion prediction between the physics-based simulation method and empirical ground motion models suggests the former is a viable approach for generating site-specific ground motions for geotechnical and structural response history analyses.

scholarly journals Development of two components acceleration time histories for Semarang, Indonesia, due to Semarang fault earthquake scenarios using 30 meters soil deposit model

2018 ◽  
Vol 159 ◽  
pp. 01043
Author(s):  
Windu Partono
Keyword(s):  
Site Response ◽  
Historical Earthquakes ◽  
Structure Design ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Acceleration Time ◽  
Earthquake Scenarios ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Deposit Model

Development of surface acceleration time histories is important for dynamic analysis of structure design and evaluation. Acceleration time histories usually developed from seismograph records due to specific earthquake event. Following the research conducted by Team for Revision of Seismic Hazard Maps of Indonesia 2010 and 2016, Lasem fault and Semarang fault are two closest and dangerous shallow crustal fault earthquake sources which must be taken into account for seismic mitigation of Semarang. This paper presents the development two components surface acceleration time histories for Semarang caused by Semarang fault earthquake scenarios, with magnitude from 6 Mw to 7 Mw and maximum epicentre distance 15 Km. This research was performed by conducting deterministic hazard analysis, response spectral matching and site response analysis to obtain a pair of modified acceleration time histories. Site response analysis was performed by conducting 30 meters soil deposit model by taking the assumption that the position of bedrock elevation is 30 meters below the surface layer. Modified acceleration time histories were developed from a pair time histories (North-South/NS and East-West/EW direction) collected from worldwide historical earthquakes. Modified time histories were developed due to limited time histories data caused by Semarang fault earthquake source.

Nonlinear site effects on strong ground motion at a reclaimed island

2000 ◽  
Vol 37 (1) ◽  
pp. 26-39 ◽  
Author(s):  
Jun Yang ◽  
Tadanobu Sato ◽  
Xiang-Song Li
Keyword(s):  
Ground Motion ◽  
Site Effects ◽  
Site Response ◽  
Ground Motions ◽  
Soil Liquefaction ◽  
Large Strains ◽  
Stress Strain ◽  
Element Analysis ◽  
Soil Response ◽  
Kobe Earthquake

Recently there has been an increased interest in the study of the nonlinearity in soil response for large strains through in situ earthquake observations. In this paper, the downhole array acceleration data recorded at a reclaimed island, Kobe, during the 1995 Kobe earthquake are used to study nonlinear site effects. Particular attention is given to the liquefaction-induced nonlinear effects on the recorded ground motions. By using the spectral ratio and the spectral-smoothing technique, the characteristics of the ground motions are analyzed. It is shown that the peak frequencies in spectral ratios were shifted to lower frequencies when the strongest motions occurred. The increase in the predominant period was caused primarily by a strong attenuation of low-period waves, rather than by amplification of long-period motions. Based on the spectral analyses, the nonlinearity occurring in the shallow liquefied layer during the shaking event is identified, manifested by a significant reduction of the shear modulus. A fully coupled, inelastic, finite element analysis of the response of the array site is carried out. The stress-strain histories of soils and excess pore-water pressures at different depths are calculated. It is suggested that the stress-strain response and the build up of pore pressure are well correlated to the variation of the characteristics of ground motions during the shaking history.Key words: site response, ground motion, nonlinearity, soil liquefaction, array records, Kobe earthquake.

Significance of ground motion time step in one dimensional site response analysis

2012 ◽  
Vol 43 ◽  
pp. 202-217 ◽  
Author(s):  
Camilo Phillips ◽  
Albert R. Kottke ◽  
Youssef M.A. Hashash ◽  
Ellen M. Rathje
Keyword(s):  
Ground Motion ◽  
Site Response ◽  
Site Response Analysis ◽  
Response Analysis ◽  
Time Step ◽  
One Dimensional ◽  
Motion Time
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