Open AccessRegional dispersion of first‐order overtone Rayleigh waves
Author(s) -
Okal Emile A.,
Jo BongGon
Publication year - 1983
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.1983.tb03796.x
Subject(s) - asthenosphere , geology , overtone , subduction , dispersion (optics) , rayleigh wave , seismology , trench , phase velocity , range (aeronautics) , continental shelf , surface wave , geophysics , geodesy , tectonics , oceanography , optics , layer (electronics) , physics , chemistry , materials science , organic chemistry , astronomy , composite material , spectral line
Summary Records of the first Rayleigh overtone in the 70–110 s period range, following deep subduction zone events, are analysed through standard surface wave techniques to retrieve dispersion characteristics. In the oceanic environment, our data are in general agreement with published models obtained from regionalization of fundamental Rayleigh wave paths. A general increase in phase velocity with age is observed, with a somewhat smaller effect on group velocities. Continental and trench area data are processed through a regionalization scheme, indicating that the difference between average continental and oceanic velocities (both phase and group) is about 0.2 km s −1 at periods of the order of 95 s. An investigation of a set of simple models, allowing structural heterogeneities between oceans and continents down to variable depth, suggests that they probably do not extend past the bottom of the asthenosphere (250 km).