Seismic borehole and surface equipment

Tomography

Provides high spatial resolution images of P- and S-wave velocities to delineate geological structures

Seismic tomography provides high-resolution 2D or 3D images of seismic velocities between boreholes. The method is used to delineate geological structures, to map cavities and weak zones and to specify mechanical soil and rock properties.

Geophysicists and engineers apply this method to investigate the foundation and underlying rock of buildings and bridges in order to characterize the subsurface before infrastructure is built and to image time-dependent processes.

Crosshole

Provides high 1D resolution depth profile of P- and S-wave velocities to determine soil dynamic parameters

The crosshole test provides a depth profile of shear wave velocities (VS) and compressional wave velocities (VP) between boreholes at a high vertical resolution. The method is used to determine soil dynamic parameters, such as shear modulus, Poisson ratio and Young’s modulus. Engineers use these key parameters to predict the response of soils to dynamic loading.

Downhole

Provides standard 1D resolution depth profile of P- and S-wave velocities to determine soil dynamic parameters

The downhole test provides shear wave velocities (VS) and compressional wave velocities (VP) for geological layers along a single borehole. Soil dynamic parameters, such as shear modulus, Poisson ratio and Young’s modulus can be determined to evaluate the soil’s response to dynamic loading. The downhole test has a lower vertical resolution than the crosshole test.

Surface Seismic

Provides 1D profiles or spatial images about material parameters and lithological characteristics

Near-surface seismic surveying enable the mapping of seismic velocities, related material properties and geological structures. Refraction, reflection and MASW (multichannel analysis of surface waves) are capable methods for near-surface engineering and exploration applications.