The Kumaun-Garhwal region of Himalaya falls in the central seismic gap of Himalaya where the probability of occurrence of the great earthquake has been estimated as 31% in a 50-year time window. This underlines the importance of evaluation of seismic hazard in this region. One-dimensional (1D) site response functions provide one-dimensional predictions in a 3D environment and play an important role in assessing the seismic hazard of a region. In the present study, 1D site response functions have been estimated for the Kumaun-Garhwal region using 56 local earthquakes recorded at 14 sites. Ten sites, out of the 14 sites, are situated in Garhwal Himalaya, 3 sites are located in adjacent Kumaun Himalaya and 01 in Indo-Gangetic plain. The widely used horizontal to vertical spectral ratio technique has been adopted here for this purpose. The seismic spectral amplification levels have been obtained at the predominant frequency as well as at five different frequencies corresponding to different types of buildings. The average site spectral amplification levels at the predominant frequency for the sites in higher Himalaya, lesser Himalaya, and in outer Himalaya are found to be 3.94, 4.43, and 5.98 respectively. These estimated values are correlated with rock/soil types in these three sub-divisions of Himalaya. The only site (Deoband) situated in the Indo-Gangetic plain gives the site spectral amplification level of 7.17 at predominant frequency. The seismic hazard to different story buildings in the region based on the estimated site spectral amplification levels is discussed. The computed site spectral amplification functions are useful for estimating the earthquake source parameters and for the simulating techniques for earthquake strong ground motions.

中文翻译：

---

估计印度喜马拉雅山的库玛恩-加尔瓦尔地区的站点响应功能

喜马拉雅山的库玛恩-加尔瓦尔地区位于喜马拉雅山的中央地震带，据估计，在50年的时间范围内，发生大地震的概率为31％。这突出了评估该地区地震危险的重要性。一维（1D）站点响应功能可在3D环境中提供一维预测，并在评估区域的地震危险中起重要作用。在本研究中，使用在14个地点记录的56次本地地震，估计了Kumaun-Garhwal地区的一维站点响应函数。14个站点中的10个站点位于Garhwal Himalaya，3个站点位于相邻的Kumaun Himalaya和01在印度恒河平原。为此，这里采用了广泛使用的水平/垂直光谱比技术。在主要频率以及对应于不同建筑物类型的五个不同频率下获得了地震频谱放大水平。高喜马拉雅山，小喜马拉雅山和喜玛拉雅山外围地区的主要频率处的平均部位光谱放大水平分别为3.94、4.43和5.98。这些估计值与喜马拉雅山这三个分区的岩石/土壤类型相关。位于印度恒河平原的唯一站点（Deoband）在主要频率处的站点频谱放大水平为7.17。讨论了基于估计站点频谱放大水平对区域内不同楼层建筑物的地震危害。