We here propose a method for rapid, high-frequency seismogram generation that makes use of an algorithm to automatically generate an exhaustive set of seismic phases that produce an appreciable amplitude on the seismogram. The method uses a hierarchical order of rays and seismic phases generation, taking into account some existence constraints for a ray-path and some physical constraints. To compute synthetic seismograms, the COMRAD code (from the Italian: “COdice Multifase per il RAy-tracing Dinamico”) uses as its core a dynamic ray-tracing code. To validate the code, we have computed in a layered medium synthetic seismograms using both COMRAD and a code which computes the complete wavefield by the discrete wavenumber method. The seismograms are compared according to a time-frequency misfit criteria based on the continuous wavelet transform of the signals. The comparison shows that the ray-theory seismogram is enough complete and moreover, the time for the computing of the synthetics using the COMRAD code (truncating the ray series at the 10th generation) is 3-4-fold less than that needed for the Axitra code (to a frequency of 25 Hz).
|Titolo:||Development of a multi-phase dynamic ray-tracing code|
|Data di pubblicazione:||2008|
|Appare nelle tipologie:||2.1 Contributo in volume (Capitolo o Saggio)|