Introduction. The problem caused by soft soils within the city of Cuenca, is increasingly increased due to the population expansion of the city, especially in two peripheral areas: Challuabamba and Nulti, presenting cases of slope instability, serious cracks in masonry, sinkholes etc. Target. In this article, an analysis is made of how seismic waves are amplified or attenuated in soft soils and allow us to determine the highest peak of frequencies and therefore calculate the fundamental period of the soil. Methodology. To determine the seismic records, it was done through geophysical tests of Seismic Refraction using the MASW method, six seismic lines were laid, two in Challuabamba and four in Nulti, which allowed us to determine the compression wave velocities (Vp), shear (Vs), and various elastic parameters of the soils studied. Results. With the elastic parameters calculated, and through the DEGTRA program, a mathematical modeling was carried out, using the Theoretical Transfer Functions, the result was the determination of the maximum frequency of the soil and in turn the period of the same, and make a comparison with the fundamental period calculated by seismic refraction. Conclusion. Through the Transfer Functions we can model how seismic waves are amplified or attenuated when transmitted within a soil stratum when perceiving a telluric movement, which are present day by day in our daily lives and especially in areas with a high seismic hazard., where site effects are the shapers of wave amplifications in soft soils.