A Practical Method to Estimate Strong Ground Motions after an Earthquake, Based on Site Amplification and Phase Characteristics

2011 ◽  
Vol 101 (2) ◽  
pp. 688-700 ◽  
Author(s):  
Y. Hata ◽  
A. Nozu ◽  
K. Ichii
Keyword(s):  
Ground Motions ◽  
Practical Method ◽  
Site Amplification ◽  
Strong Ground Motions ◽  
Strong Ground

Nonlinear site amplification at CCHG observed by strong ground motions during the 2011 off the Pacific coast Tohoku earthquake

2015 ◽  
Author(s):  
Kohei Tanaka ◽  
Seiji Tsuno ◽  
Hiroaki Yamanaka ◽  
Kosuke Chimoto ◽  
Makoto Kamiyama ◽  
...  
Keyword(s):  
Pacific Coast ◽  
Ground Motions ◽  
Tohoku Earthquake ◽  
Site Amplification ◽  
Strong Ground Motions ◽  
The Pacific ◽  
Strong Ground

scholarly journals Analysis of Site Amplification and Nonlinear Response Based on Ground Motion Records at MYGH10 Station in Japan

2021 ◽  
Author(s):  
Shiliang Zhang ◽  
Dongwang Tao ◽  
Quancai Xie ◽  
Qiang Ma ◽  
Fuchen Wang
Keyword(s):  
Ground Motion ◽  
Amplification Factor ◽  
Ground Motions ◽  
Spectral Ratio ◽  
Site Amplification ◽  
Predominant Frequency ◽  
Strong Ground Motions ◽  
Ground Motion Records ◽  
Site Amplification Factor ◽  
Strong Ground

Abstract Strong horizontal ground motions with the peak ground acceleration (PGA) larger than 1400 gal were observed at Yamamoto (MYGH10) station during the February 2021 Mj 7.3 off the east coast of Honshu, Japan, Fukushima earthquake. Firstly, in this paper, we discussed and verified the theoretical assumptions of the “Nakamura” method under weak and strong ground motions. The site amplification factor of the MYGH10 station was estimated using the surface horizontal-vertical spectral ratio (HVSR) and the surface-to-borehole spectral ratio (SBSR), and the corrected HVSRC, respectively. Meanwhile, the reasons for underestimating the site amplification factor when using HVSR were explained. The vertical amplification phenomenon of seismic P-wave in the high-frequency band was analysed under weak and strong ground motions. Secondly, we utilized HVSR, SBSR, and theoretical transfer function (TTF) based on the 1D wave propagation theory to study the nonlinear site response of MYGH10 station under the mainshock of the Fukushima earthquake and the historically weak and strong ground motions, respectively. The changes in frequencies and amplitudes of the spectral ratio curves when nonlinearities were occurring at the site were analysed and compared using the spectra ratio curves of weak ground motion records and TTF as references. Finally, the recovery of the site after strong nonlinearity was also evaluated by comparing the spectral ratio curves of aftershocks records. We found that the most significant amplification factor of the site increased from 7 to more than 10, and the predominant frequency decreased from 10 Hz to 3.8 Hz under the mainshock of the Fukushima earthquake. The predominant frequency returned to the previous value within three days after the mainshock, but the amplification factor did not.

scholarly journals Broadband Strong-Motion Prediction for Future Nankai-Trough Earthquakes Using Statistical Green’s Function Method and Subsequent Building Damage Evaluation

2021 ◽  
Vol 11 (15) ◽  
pp. 7041
Author(s):  
Baoyintu Baoyintu ◽  
Naren Mandula ◽  
Hiroshi Kawase
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Nankai Trough ◽  
Ground Motions ◽  
Building Damage ◽  
Steel Buildings ◽  
Ground Acceleration ◽  
Attenuation Relations ◽  
Strong Ground Motions ◽  
Strong Ground

We used the Green’s function summation method together with the randomly perturbed asperity sources to sum up broadband statistical Green’s functions of a moderate-size source and predict strong ground motions due to the expected M8.1 to 8.7 Nankai-Trough earthquakes along the southern coast of western Japan. We successfully simulated seismic intensity distributions similar to the past earthquakes and strong ground motions similar to the empirical attenuation relations of peak ground acceleration and velocity. Using these results, we predicted building damage by non-linear response analyses and find that at the regions close to the source, as well as regions with relatively thick, soft sediments such as the shoreline and alluvium valleys along the rivers, there is a possibility of severe damage regardless of the types of buildings. Moreover, the predicted damage ratios for buildings built before 1981 are much higher than those built after because of the significant code modifications in 1981. We also find that the damage ratio is highest for steel buildings, followed by wooden houses, and then reinforced concrete buildings.

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