A Comparative Analysis for Defining the Sliding Surface and Internal Structure in an Active Landslide Using the HVSR Passive Geophysical Technique in Pujilí (Cotopaxi), Ecuador

Geophysical techniques were employed to analyze one of the landslides that affected main access road Pujilí (Ecuador). A passive seismic technique was utilized test a total 70 horizontal vertical spectral ratio (HVSR) points, complemented by an active seismic-refraction profile and multichannel analysis surface waves (MASW) survey. The results from geophysical surveys facilitated determination shear-wave-velocity value for materials in motion. However, HVSR provided fundamental frequency fo amplification Ao values ground. Nakamura (1989) relationship applied obtain thickness sediments over compact material terrain two-layer model. Additionally, constrained models shear-wave velocity (Vs) distribution landslide area, obtained surveys, used invert ellipticity curves. this inversion compared with those applying equation. landslide-rupture delineated each type analysis, which verified correlation minimal differences between three proposed studies, thus validating procedure. directivity microtremor signals also analyzed, demonstrating internal structure sliding material. Furthermore, ability slide concerning Kg parameter (vulnerability index, Nakamura, 1989) studied. usefulness defining structures determining areas most significant instability demonstrated. Overall, is considered valuable when conducting early studies helpful rupture plane while remaining simple, fast, economical technique.