scholarly journals Specific distribution of ground motion during the 1995 Kobe Earthquake and its generation mechanism

1998 ◽  
Vol 25 (6) ◽  
pp. 785-788 ◽  
Author(s):  
T. Furumura ◽  
K. Koketsu
Keyword(s):  
Ground Motion ◽  
Generation Mechanism ◽  
Kobe Earthquake ◽  
Specific Distribution

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.

scholarly journals Seismic Ground Response Analysis of Input Earthquake Motion and Site Amplification Factor at KUET

2021 ◽  
pp. 45-54
Author(s):  
Sonia Akter
Keyword(s):  
Ground Motion ◽  
Shear Wave Velocity ◽  
Amplification Factor ◽  
Site Response ◽  
Site Amplification ◽  
Response Analysis ◽  
Ground Response ◽  
Ground Response Analysis ◽  
Kobe Earthquake ◽  
Earthquake Motion

Ground motion is the movement of the earth's surface due to explosions or the propagation of seismic waves. In the seismic design process, ground response analysis evaluates the impact of local soil conditions during earthquake shaking. However, it is difficult to determine the dynamic site response of soil deposits in earthquake hazard-prone areas. Structural damage has a great influence on the selection of input ground motion, and in this study, the importance of bedrock motion upon the response of soil is highlighted. The specific site response analysis is assessed through “DEEPSOIl" software with an equivalent linear analysis method. Furthermore, four input motions including Kobe, LomaGilroy, Northridge, and Chi-Chi were selected to obtain normalized response spectra. This study aims to obtain the site amplification of ground motion, peak spectral acceleration (PSA), and maximum peak ground acceleration (PGA) based on shear wave velocity from the detailed site-specific analysis of Bangabandhu Sheikh Mujibor Rahman hall at Khulna University of Engineering & Technology. The maximum shear wave velocity obtained was 205 m/s while the amplification factor varied from 4.01 (Kobe) to 1.8 (Northridge) for rigid bedrock properties. Furthermore, the Kobe earthquake produced the highest (4.3g) PSA and the Northridge earthquake produced the lowest (1.08g) PSA for bedrock, with Vs=205 m/s. The surface PGA values were acquired in the range of 0.254g (Northridge) to 0.722g (Kobe), and the maximum strain values for Kobe earthquakes were in the range of 0.016 to .303. Therefore, the surface acceleration values were very high (>0.12g) for the Kobe earthquake motion.

Comparison of Loss Estimation for Various Seismic Source Models: The Case of the 1995 Hyogo-ken Nanbu Earthquake

2003 ◽  
Vol 19 (1) ◽  
pp. 67-85
Author(s):  
Ken Hatayama ◽  
Shinsaku Zama
Keyword(s):  
Ground Motion ◽  
Strong Ground Motion ◽  
Seismic Source ◽  
Loss Estimation ◽  
Kobe Earthquake ◽  
Finite Fault ◽  
Seismic Source Models ◽  
Future Earthquake ◽  
Source Models ◽  
Strong Ground

We compare the distribution of damage to housing caused by the 1995 Hyogo-ken Nanbu (Kobe) earthquake with those estimated for several source models proposed for this earthquake. This comparison aims at identifying source models that can provide loss estimates that are most appropriate for planning emergency response activities just after earthquakes and/or for preparing effective countermeasures for mitigation of future earthquake disasters. The results suggest the necessity of finite-fault slip models that can reproduce or predict accurately strong ground motion within a frequency range closely related to damage. The loss estimation just after earthquakes based on source models can be counted on in areas without dense strong-ground-motion observation networks. Even with the dense networks, source models will also be useful for accurate loss estimation in the immediate vicinity of earthquake source faults.

scholarly journals Performance of NGA Models in Predicting Ground Motion Parameters of The Strong Earthquake

2019 ◽  
Vol 5 (3) ◽  
pp. 227
Author(s):  
Lindung Zalbuin Mase
Keyword(s):  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Strong Earthquake ◽  
Ground Acceleration ◽  
Strong Earthquakes ◽  
Ground Motion Parameters ◽  
Kobe Earthquake ◽  
Residual Values ◽  
Motion Parameters ◽  
Predicted Values

Next Generation Attenuation (NGA) West 1 and 2 models are employed to predict the ground motion parameters of strong earthquake during the 6.9 Mw Kobe Earthquake in 1995. This study is initiated by collecting the data of ground motion parameters of the earthquake. Furthermore, the ground motion prediction is performed by using the NGA models. There are three ground motion parameters observed, i.e. peak ground acceleration (PGA), spectral acceleration (SA) at 0.2 second and SA at 1 second. The performances of the models are evaluated by using the Residual Values and Root Mean Square (RMS) Error. The results show that the NGA models could predict the ground motion parameters quite appropriately. It can be seen from the correlation values of the observed and the predicted values, which is relatively consistent each other, especially for peak ground acceleration. In general, this study could recommend the procedure in selecting the attenuation model for strong earthquakes. The study framework could be implemented to predict the ground motion in other regions. 

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