Open AccessRemarks on the travelling wave decomposition
Author(s) -
Pollitz Fred F.
Publication year - 2001
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1046/j.1365-246x.2001.00271.x
Subject(s) - physics , traveling wave , wave propagation , classical mechanics , geophysics , longitudinal wave , mode (computer interface) , geology , mechanics , mathematical analysis , optics , computer science , mathematics , operating system
SUMMARY In elastic wave propagation on a spherically symmetric earth model, a normal mode sum is converted into a sum of equivalent travelling waves by means of a travelling wave decomposition (TWD). For two decades, seismologists have assumed that each travelling wave in the TWD is associated with only real phase velocities, that is, no evanescent waves travel on a spherically symmetric earth model. In this paper, this assumption is proven false. By including a countably infinite set of waves travelling as evanescent waves, several conceptual difficulties confronting the TWD are resolved.