The micro-seismic hazard estimation including quantification of the ground motion amplification has been conducted at Ahmedabad city based on near-surface characterization/soil modeling. The city has experienced substantial damage in the course of the 2001 Bhuj earthquake. A total of 20 boreholes were drilled in the city up to the depths of 40–80 m. A five-fold methodology is adopted: (1) Assessment of the seismic perspective of the area under study, (2) demarcation of the engineering bed layer (EBL) through geophysical (seismic) surveys and the soil properties, (3) soil modeling using geotechnical and the geophysical parameters, (4) assessment of the strong ground motion at EBL through simulation considering far-field earthquake scenarios and near-field earthquakes scenario and (5) surface strong-motion estimation by ground response analysis based on equivalent-linear approach. The near-surface soil models were prepared from the borehole logs, shear-wave velocity estimated from the seismic survey and the soil properties like soil classification and density. The strong motion at EBL is computed by simulating seismotectonically justified scenario earthquakes through the stochastic finite-fault source modeling technique using the region-specific input parameters. The surface-strong motion is estimated by performing ground response analysis (with SHAKE) at every borehole using EBL-strong motion and prepared soil models. The EBL was found varying from 28 to 54 m in depth in Ahmedabad city. The effect of far-field and near-field earthquake sources was considered for assessing the hazard. To compensate for the uncertainty, a total of 108 and 81 input parametric combinations for near-field earthquake scenarios, and far-field earthquake scenarios, respectively have been considered for estimating the strong motion at EBL. The peak ground acceleration (PGA) of 52–111 cm/s² and 108 cm/s² are estimated at EBL due to near-field earthquake scenarios and far-field earthquake scenarios, respectively. The PGA through ground response analysis at surface level is found to be varying from 101 to 279 cm/s² for near-field earthquake scenarios and, 118–161 cm/s² for the far-field earthquake scenarios. The spectral acceleration (SA) (at surface level) has also been calculated for damping of 5%. The average SA distribution maps for 0.2 s (1–2 story), 0.55 s (4–5 story), 1 s (high rise) and 1.25 s period (large structures) have been prepared for both types of scenario earthquakes. The strong motion amplification is computed to be in the range of 1.6–3.3 for near-field earthquake scenarios and 2.2–3.0 for near-field earthquake scenarios.

在艾哈迈达巴德市，已根据近地表特征/土壤模型对微地震危险性进行了估算，包括对地震动放大的量化。在2001年的布杰地震中，这座城市遭受了严重破坏。该城市在40-80 m的深度总共钻了20个钻孔。采用五种方法：（1）评估研究区域的地震视角；（2）通过地球物理（地震）勘测和土壤特性对工程层（EBL）进行划分；（3）土壤建模使用岩土工程和地球物理参数，（4）通过考虑远场地震场景和近场地震场景的模拟评估EBL的强地面运动，以及（5）通过基于等效线性方法的地面响应分析估算地表强运动。通过钻孔测井，通过地震勘测估算的剪切波速度以及土壤性质（例如土壤分类和密度），可以创建近地表土壤模型。EBL的强运动是通过使用特定于区域的输入参数，通过随机有限故障源建模技术模拟地震构造合理的情景地震来计算的。通过使用EBL强运动和准备好的土壤模型在每个钻孔中执行地面响应分析（使用SHAKE），可以估计表面强运动。在艾哈迈达巴德市发现的EBL深度从28到54 m不等。为了评估灾害，考虑了远场和近场地震源的影响。为了补偿不确定性，已考虑分别针对近场地震场景和远场地震场景分别使用108和81个输入参数组合来估计EBL的强运动。峰值地面加速度（PGA）为52–111 cm / s由于近场地震场景和远场地震场景，在EBL分别估计²和108 cm / s ²。通过在表面水平地响应分析的PGA被发现是改变从101至279厘米/秒²为近场地震场景和，118-161厘米/秒²对于远场地震场景。还针对5％的阻尼计算了光谱加速度（SA）（在表面水平）。对于两种类型的情景地震，均已准备了0.2 s（1-2层），0.55 s（4-5层），1 s（高层）和1.25 s周期（大型建筑物）的平均SA分布图。计算得出的强运动放大率在近场地震场景中为1.6–3.3，在近场地震场景中为2.2–3.0。