Open AccessInterpretation of Sa on a continental structure
Author(s) -
Nakanishi K. K.,
Schwab F.,
Kausel E. G.
Publication year - 1976
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1976.tb01270.x
Subject(s) - seismogram , geology , interpretation (philosophy) , seismology , phase velocity , attenuation , dispersion (optics) , geophysics , group velocity , microseism , phase (matter) , physics , optics , quantum mechanics , computer science , programming language
Summary Earlier work on the interpretation of Sa for continental structures is completed by including theoretical seismograms in the interpretation, along with multimode Love wave dispersion, attenuation and source excitation. Further, it is demonstrated that Sa is not a low‐velocity zone channel wave by generating theoretical seismograms, which include this phase, with a structure containing no low‐velocity zone. Sa is a seismic phase which seems to be influenced primarily by the abrupt velocity increase at a depth in the 400–450‐km region. This interpretation is evaluated by computing eigenfunctions, group velocities, and source excitations for a model with a single layer over a high velocity region; the results compare favourably with those for the realistic model of the Earth.