“Basin effects” refers to trapped and reverberating earthquake waves in soft sedimentary deposits overlying convex depressions of the basement bedrock, which significantly alter frequency content, amplitude, and duration of seismic waves. This has played an important role on shaking duration and intensity in past earthquakes such as the M_w 8.0 1985 Michoa'can, Mexico, M_w 6.9 1995 Kobe, Japan, and M_w 7.8 2015 Gorkha, Nepal. Although the phenomenon has been understood and addressed in the literature, it has not been fully incorporated in seismic hazard analysis, and Ground Motion Prediction Equations (GMPE). In this study, we perform an extensive parametric study on the characteristics of surface ground motion associated with basin effects using finite element simulations. We use an elastic medium subjected to vertically propagating SV plane waves and utilize idealized basin shapes to examine the effects of basin geometry and material properties. We specifically study the effects of four dimensionless parameters, the width-to-depth (aspect) ratio, the rock-to-soil material contrast, a dimensionless frequency that quantifies the depth of the basin relative to the dominant incident wavelength, and a dimensionless distance quantifying distance of the basin edges relative to the dominant wavelength. Our results show that basin effects can be reasonably characterized using at least three independent parameters, each of which can significantly alter the resultant ground motion. To demonstrate the application of dimensional analysis applied here, we investigate the response of the Kathmandu Valley during the 2015 M_w 7.8 Gorkha Earthquake in Nepal using an idealized basin geometry and soil properties. Our results show that a simplified model can capture notable characteristics of the ground motion associated with basin effects which suggests that such studies can provide useful insights, relevant to the parameterization of basin effects in GMPEs and design code provisions.

“盆地效应”是指在基岩凸凹上覆的软沉积物中捕获并回荡的地震波，这会显着改变地震波的频率含量，振幅和持续时间。这已经演奏了惊天过去地震持续时间和强度具有重要作用，如中号_W¯¯ 8.0 1985 Michoa'can，墨西哥，中号_W¯¯ 6.9 1995年日本神户，和中号_{w ^}7.8 2015尼泊尔戈尔卡。尽管该现象已在文献中得到理解和解决，但尚未完全纳入地震危险性分析和地震动预测方程（GMPE）中。在这项研究中，我们使用有限元模拟对与盆地效应相关的地表地面运动特征进行了广泛的参数研究。我们使用承受垂直传播的SV平面波的弹性介质，并利用理想的盆地形状来检验盆地几何形状和材料特性的影响。我们专门研究了四个无因次参数的影响，即宽深比（纵横比），岩土材料的对比度，无量纲频率，该频率量化了盆地相对于主要入射波长的深度，无量纲距离量化盆边缘相对于主波长的距离。我们的结果表明，至少可以使用三个独立的参数来合理地描述盆地效应，每个参数都可以显着改变合成的地面运动。为了说明此处应用的维分析的应用，我们调查了2015年加德满都谷地的响应中号_W¯¯ 7.8廓尔喀地震在尼泊尔使用理想化盆地的几何形状和土壤性质。我们的结果表明，简化的模型可以捕获与盆地效应相关的地震动的显着特征，这表明此类研究可以提供有用的见解，与GMPE和设计规范中盆地效应的参数化有关。