The Seismic Refraction Method is a geophysical technique used to determine the depth and velocity of subsurface layers by analyzing the travel times of seismic waves. Geological layers tend to have velocity contrasts, which are detectable by seismic refraction. The relative velocities of subsurface layers are typically:
Seismic Reflection is a method of exploration geophysics that estimates the properties of the Earth's subsurface from reflected seismic waves.
MASW uses surface waves (Rayleigh waves) to characterize the shear-wave velocity (Vs) of the subsurface to develop 2D models of Vs structure.
pVs uses passive seismic energy (ambient vibrations) to model the shear-wave velocity structure without an active source.
The Horizontal-to-Vertical Spectral Ratio (H/V) method is a passive seismic technique used to determine the depth of bedrock by estimating subsurface resonance frequencies from ambient seismic noise. The amplitude spectra of the horizontal and vertical components of ground motion is analyzed to model subsurface stratigraphy.
These seismic techniques provide a powerful, non-invasive suite of tools to characterize subsurface conditions for geotechnical and environmental purposes. By analyzing seismic wave behavior, they provide insights into the depth, composition, and structure of geological layers.
