6:15 PM - 7:30 PM
[SSS25-P08] Nonlinear Site Response Analysis in Tokyo Meteropolitan Area Using Equivalent Linear Approach
Keywords:Nonlinear site effect, Plate boundary earthquake, Intra-slab earthquake
Site response analyses were achieved by an equivalent linear method using DYNEQ program developed by Yoshida and Suetomi (1996). G-γ and h-γ relationships of Central Disaster Mitigation Council are recognized to express the shear deformation of soil (clay, sand, and gravel). Resultant waveforms on free surface shows a systematic dependence on thickness of the soft structure above the engineering base. Large amplification is dominant at corresponding short periods above shallow soft structure, whereas the peak amplitudes shifted to longer periods for sites located above deep soft structure. Nonlinear site effects were typically obvious at short periods of approximately 0.2 s and shorter. The deformations mostly concentrated in the shallow 20 m of the soil inferred from maximum shear strains analysis. Our analysis showed the considerable effects of the non-linear response of surface layers to large seismic inputs on the engineering base.