Applied Geophysics

Seismics

Elastic waves are emitted by an artifical source (eg. sledge hammer, drop down). They propagate through the subsurface, where they may be reflected, refracted or diffracted. Those waves, which reach again the surface, are recorded with sensors (geophones, hydrophones).

There are four main applications:

  • reflection seismic / steep angle seismic
    Aim is a image of the layer interfaces and boundary in the subsurface. Observed reflections and diffractions are identified in the data and analysed. Additional a velocity model of the subsurface is derived.
  • refraction seismic / wide angle seismic
    Aim is a 2D or 3D velocity model of the subsurface. Traveltimes of first and later onsets are picked and analysed.
  • surface wave seismics
    Aim is a 2D or 3D velocity model of the subsurface. The frequency-dependence of the propagation velocity are analysed.
  • full waveform inversion
    Aim is a model of the subsurface. A subsurface model is searched by the mean of inversion, which reproduces the observed full wavefield.