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Most of the densely populated urban areas are located on or near sediment-filled basins (Mexico, Kathmandu, etc.). The observations of past earthquakes have shown that the ground motions recorded in basins can be affected by many factors such as mechanical properties of sediment materials, faults rupture scenarios, depth, and distance of epicenter from the basin. Even the earthquakes originating at distant epicenters, the urban areas in sedimentary basins experienced long and stronger ground motions due to basin amplification. One of the examples is the 1985 Michoacán Mexico earthquake (Atienza et al., 2016; Rial et al., 1992), where Mexico City, sitting on a basin at a distance more than 350 km from the epicenter, suffered a Mercalli intensity of IX. The basin amplification also increases the duration of ground shaking (Atienza et al., 2016; Kaneko et al., 2018, 2019), which is also observed in this study by numerical simulations. Studies have observed that, the basin amplified ground motion increases the consequences of an earthquake on civil infrastructure (Marafi et al., 2017; Parla et al., 2022; Somala et al., 2022). The basin amplification is largly controlled by stiffness and damping of material, and depth of the sedements (Jakka et al., 2015).
The combined effect of impedance contrast between the basin and surrounding bedrock and wave focusing due to the limited extent of sediments are the main reasons for basin amplification (Semblat et al., 2004). The basin effect can be studied by directly investigating ground records or numerical simulations (Frankel & Vidale, 1992; Niu & Dravinski, 2003; Semblat et al., 2011). The availability and exposure of high performance computing resources, the study of seismic source and site effects has emerged in recent years(Chanda et al., 2021; Saha et al., 2022; Veggalam et al., 2021). Along with the impedance contrast, topography also plays a vital role in affecting the amplitude and pattern of basin amplification (Bard & Bouchon, 1985; Niu & Dravinski, 2003). A series of recent studies have indicated that the wave focusing and basin edge effects in sediment basins are also the leading causes of long duration ground shaking (Baher & Davis, 2003; Brissaud et al., 2020; Graves et al., 1998; Kawase, 1996; Stephenson et al., 2000).