This paper investigates the seismic behavior of rectangular alluvial valleys subjected to SV and SH waves. A two-dimensional dynamic analysis is performed using the linear finite element method to evaluate the response of these valleys. The primary objective of this study is to assess the influence of geometric and mechanical parameters on the seismic response of the valleys and to evaluate the response ratio under SV and SH waves. Additionally, the effect of the valley shape ratio on amplification and natural period is examined, identifying the maximum amplification points on the valley surface. The results indicate that the amplification pattern is significantly affected by the valley shape ratio. As the shape ratio decreases, the natural period increases and the maximum amplification typically occurs at the valley center. The findings also reveal that the dynamic response of valleys depends on the type of incident wave. SH waves tend to cause higher amplifications at lower frequencies and are more sensitive to geometric variations, while SV waves exhibit more complex behavior near the valley’s natural frequency. The analyses highlight the existence of a uniform characteristic period for surface points on the valleys, which can assist in the preliminary estimation of the natural period of alluvial valleys. This study provides essential relationships for calculating this value, offering a basis for microzonation and seismic hazard assessment in various regions.

......................................................................................................................................................................aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa vv.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa v.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa v.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa vv.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa v.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa v.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa vv.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa v.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa v.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa vv.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa v.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa v.aa aa aa .aa aa aa .aa aa aa .aa aa aa .aa aa aa