SUMMARY

Evaluating the basement effect in the Hồ Chí Minh City area under the impact of earthquakes by the modelling approach

Mai Xuân Bách, Lê Văn Dũng

In this article, we introduce testing results of method of evaluating the local basement effect under the impact of earthquakes by the modelling approach. This approach is based on the construction of model imitating the process of generation and propagation of seismic waves from source to observation point, with the use of known initial informations on conditions of engineering geology and deep structure of studied areas.

The calculated maximal response spectra ratio (RSR) of the Hồ Chí Minh City area has the values of about 0.9-3.3, corresponding to the frequency from 0.5-3.0 Hz (cycle 0.3-1.0 sec) depending on the different areas.

- In the Củ Chi and Hóc Môn areas the maximum RSR for radial component is 1.3-2.2, with corresponding frequency ≈ 3.0 Hz, horizontal component: 1.2-2 Hz, with corresponding frequency: 3.0-5.0 Hz, and vertical component: 1.5-1.8, with corresponding frequency: 2,0-4,0 Hz.

- In the central area of Hồ Chí Minh City, the maximum RSR for radial component is 1.3-3.0, with corresponding frequency: 1.0-3.5 Hz, horizontal component is 1.3-3.0, with corresponding frequency: 3.0 Hz, and vertical component is 1.5-2.0, with corresponding frequency: 2.0-3.0 Hz.

- In the Cần Giờ area, the maximum RSR for radial component is 3-4.8, with corresponding frequency: 2.0-2.8 Hz, horizontal component is 2.5-3.2, with corresponding frequency: 1.5-2.8 Hz and vertical component is 2.2-3.4, with corresponding frequency: 1.8- 3.0 Hz.

- In the Thủ Đức area, the maximum RSR for radial component is 1.2-2.2, with corresponding frequency: 2.0-3.0 Hz, horizontal component is 1.2-2.4, with corresponding frequency: 2-3 Hz, and vertical component is 1-2, with corresponding frequency: 1.0-2.5 Hz.

Người biên tập: TS. Nguyễn Đức Vinh.