A combination of seismic refraction and ambient noise methods to detect landslide-prone materials

Abstract

A portion of the west of Mexico City is densely populated in an abrupt topography, whose volcano-sedimentary materials increase the likelihood of landslides. We exploited the geometry of a quadrangular geophones array to apply Seismic Refraction Tomography (SRT) and Ambient Noise Tomography (ANT) methods and explore the extent of landslide-prone materials. The results show low-velocity areas (Vs < 100 m/s, being Vs group velocities) associated with materials that have lost their resistance due to the increase in pore pressure and the places where eventually, more landslides will occur (120 < Vs < 200 m/s) if mitigation work is not carried out. The most stable zones correspond to materials with velocity values greater than 250 m/s that overlap a bedrock at an average depth of 8 m. Thus, when it is not advisable to perform active source experiments, ANT can provide practical results to determine the extension of the sliding materials.

Keywords

• p-wave refraction
• seismic tomography
• seismic interferometry
• surface waves
• bedrock