Inherent Characteristics of 2D Alluvial Formations Subjected to In-Plane Motion

We investigate the inherent characteristics of 2D basins subjected to vertically propagating P-SV waves using the finite difference approach. The ratio of fundamental frequencies between an inhomogeneous basin (f₀) and its equivalent flat layers (f_h) is found to be a function of both its outer overall geometry and inner geometric formation. 2D resonance can occur in inhomogeneous basins under certain conditions, and the f₀/f_h can be used to demarcate deep from shallow basin behaviors. With other conditions remaining the same, changing a basin from homogeneity to inhomogeneity results in a lower f₀/f_h and makes 2D resonance less likely to occur.