This paper presents a scenario for the spatial variation of the fundamental frequency of the sediment deposits above the basement and the corresponding amplification as well as the average spectral amplification in different frequency bandwidths for the National Capital Territory Delhi (the capital of India). The exposed central quartzite ridge and the Yamuna River channel are responsible for very large spatial variations of the fundamental frequency in the eastern part of the National Capital Territory Delhi. At 20% of the considered sites, a good match is obtained between the fundamental frequency computed numerically using available S-wave velocities to a certain depth and their extrapolation and that obtained experimentally. The computed fundamental and dominant frequencies reveal that both medium-rise (5–10 storey) and high-rise (> 10 storey) buildings in the western part and medium-rise buildings lying in the localities east of or very near to the Yamuna River may suffer heavy to very heavy damage due to the occurrence of the double resonance phenomenon. Furthermore, 1–2-storey buildings lying on the weathered exposed quartzite rock may also suffer heavy damage during local earthquakes because of the occurrence of double resonance. The possible reasons behind the lack of earthquake damage to the Qutab Minar, the tallest brick masonry minaret in the world, over the last 800 years may be the nonoccurrence of double resonance and almost no amplification in the low frequency range. There are two localities in the western part of the National Capital Territory Delhi, namely Kanganheri-Chhawla and Buradi, wherein all sorts of buildings are highly vulnerable to earthquake damage. For the closed Chhatarpur Basin and a semiclosed basin to its northeast, formed due to exposed quartzite rock, three-dimensional (3D) simulations are required to predict the characteristics of basin-generated surface waves and their focusing effects in the Chhatarpur Basin. The average spectral amplification map developed for the 0–10 Hz bandwidth depicts a range of 2.25–4.82 in the National Capital Territory Delhi and may be directly used to transfer the estimated seismic hazard at basement to the free surface.

中文翻译：

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为地震工程目的和地震微区划计算德里 NCT 地震动放大情景

本文提出了地下室上方沉积物基频的空间变化和相应放大以及国家首都辖区德里（印度首都）在不同频率带宽下的平均频谱放大的情景。暴露的中央石英岩脊和亚穆纳河河道造成了德里国家首都辖区东部的基频出现非常大的空间变化。在 20% 的考虑地点，使用特定深度的可用 S 波速度数值计算的基频及其外推法与实验获得的基频之间获得了良好的匹配。计算出的基本频率和主频率表明，中高层（5-10 层）和高层（> 10 层）的西部建筑物和位于亚穆纳河以东或非常靠近的地方的中高层建筑物可能会因双共振现象的发生而遭受严重到非常严重的损坏。此外，位于风化裸露石英岩上的 1-2 层建筑物在局部地震中也可能由于双共振的发生而遭受严重破坏。世界上最高的砖砌尖塔Qutab Minar在过去800年中没有受到地震破坏的可能原因可能是没有发生双共振，并且在低频范围内几乎没有放大。首都辖区德里西部有两个地方，即Kanganheri-Chhawla 和Buradi，那里的各种建筑物都极易受到地震破坏。对于封闭的恰塔普尔盆地及其东北部的半封闭盆地，由于暴露的石英岩而形成，需要三维 (3D) 模拟来预测盆地产生的表面波的特征及其在恰塔普尔盆地的聚焦效应。为 0–10 Hz 带宽开发的平均频谱放大图描绘了德里国家首都辖区的 2.25–4.82 范围，可直接用于将估计的地下室地震危险转移到自由表面。