Application of high resolution geophysical prospecting to assess the risk related to subsurface deformationin Mexico City
Other literature type
Centeno-Salas, F. A.
Flores-García, W. A.
Gutiérrez-Calderón, R. I.
(issn: 2199-899X, eissn: 2199-899X)
In the eastern sector of Mexico City the sub soil consists of high
contrasting sequences (lacustrine and volcanic inter bedded deposits) that
favor the development of erratic fracturing in the surface causing damage to
the urban infrastructure. The high-resolution geophysical prospecting are
useful tools for the assessment of ground deformation and fracturing
associated with land subsidence phenomena.
The GPR method allowed to evaluate the fracture propagation and deformation
of vulcano-sedimentary sequences at different depths, the main electrical
parameters are directly related with the gravimetric and volumetric water
content and therefore with the plasticity of the near surface prospected
sequences. The active seismology prospection consisted in a combination of
Seismic Refraction (SR) and Multichannel Analysis of Surface Waves (MASW)
for the estimation of the velocity of the mechanical compressive (P) and the
shear (S) waves. The integration of both methods allowed to estimate the
geomechanical parameters characterizing the studied sequence, the Poisson
Ratio and the volumetric compressibility.
The obtained mechanical parameters were correlated with laboratory measured
parameters such as plasticity index, density, shear strength and
compressibility and, GPR and seismic profiles were correlated with the
mapped fracture systems in the study area. Once calibrated, the profiles
allowed to identify the lithological contact between lacustrine and volcanic
sequences, their variations of thicknesses in depth and to assess the
deformation area in the surface. An accurate determination of the geometry
of fracturing was of the most importance for the assessment of the
geological risk in the study area.