SPECTRAL CHARACTERISTICS OF SEISMIC WAVES AT STRONG GROUND MOTIONS

Author(s):  
Vladislav Zaalishvili
2018 ◽  
Vol 12 (04) ◽  
pp. 1841002
Author(s):  
Kiyoshi Irie ◽  
Dorjpalam Saruul ◽  
Kazuo Dan ◽  
Haruhiko Torita

In Japan, the seismic waves radiated from the fault in the surface layers above the seismogenic layer are not considered in the usual strong motion prediction. However, in the inland crustal earthquakes, the strong ground motions in the areas close to the surface faults could be influenced by the seismic waves radiated from the fault in the surface layers. Hence, we evaluated the seismic waves radiated from vertical strike-slip and dipping reverse faults in the surface layers to investigate their influence on the strong motions. The results of the strike-slip fault showed that the seismic waves of the fault normal (FN) component were larger than those of the fault parallel (FP) component in the period range of 0.5–5 s. At least, 80–90% of the FN component was attributed to the seismic wave radiated from the fault in the seismogenic layer. Almost 100% of the FP component was attributed to the seismic waves radiated from the fault in the surface layers. On the other hand, the results of the reverse fault showed that the seismic waves were not attributed to those from the fault in the surface layers.


2021 ◽  
Vol 11 (15) ◽  
pp. 7041
Author(s):  
Baoyintu Baoyintu ◽  
Naren Mandula ◽  
Hiroshi Kawase

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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