AN ALGORITHM FOR FAST TIME‐DOMAIN COMPUTATION OF ONE‐DIMENSIONAL SYNTHETIC VERTICAL SEISMIC PROFILES

The normal incidence seismic wavefields in a horizontally layered model of the earth have a well‐known matrix description if the earth model has been transformed into a layer stack built up by thin layers, all of equal traveltime. To compute a Synthetic Vertical Seismic Profile (SVSP) the wavefields are iterated through the whole layer stack by means of the matrix description, either expressed in the time domain or in the frequency domain. In conventional methods a single layer is added to a resulting stack of layers at each recursion step. However in the present algorithm, a whole layer stack is added to another layer stack at each recursion step. Improvement in computing time obtained by doing so is approximately linearly dependent on the typical number of layers between receivers. This makes the method very suitable for detailed modeling wherever high resolution of the model is desired.