<p>In this study, the effectiveness of a perfectly matched layer (PML) as a complete absorbing boundary condition is investigated for simulating radiation damping in seismic site analysis. A developed finite element dynamic analysis software named “IDAMP”, written in C programming language, is introduced. This software is capable of modeling semi-infinite media using PML, enabling both linear and equivalent linear seismic analyses. The software’s flexibility to integrate various layers and materials into models makes it a valuable resource for engineering applications. We selected and analyzed sites from the KiK-net database to comprehensively evaluate various seismic events. These analyses were conducted to assess the performance of the developed program. The results were rigorously compared with field recordings, demonstrating IDAMP’s proficiency in predicting site responses under seismic loading. A strong correlation was observed between the calculated responses and field records, highlighting the software's reliability in seismic performance assessment and infrastructure design applications for geotechnical systems. Additionally, the comparison of linear and equivalent linear analyses highlights the significance of accounting for material nonlinearity to accurately estimate ground response during earthquakes. This finding also underscores the necessity of advanced modeling techniques in seismic analysis to enhance the safety and resilience of engineered structures. This paper is part of an ongoing research, and the next part will delve into site response analysis, accounting for the nonlinear behavior sof materials.</p>