Open AccessRayleigh Wave Spectra and Group Velocity Minima, and the resonance of P waves in layered structures
Author(s) -
Hudson J. A.,
Douglas A.
Publication year - 1975
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1975.tb05856.x
Subject(s) - rayleigh wave , group velocity , physics , amplitude , love wave , surface wave , mechanical wave , plane (geometry) , resonance (particle physics) , plane wave , microseism , optics , maxima and minima , longitudinal wave , wave propagation , geometry , mathematics , geology , mathematical analysis , atomic physics , seismology
Summary. A connection is established between the group velocity of Rayleigh waves, the spectral amplitudes of surface waves generated by a source, and the resonance of vertically travelling P waves. It implies that a minimum in a group velocity curve is reflected in the spectral amplitudes as a maximum. That this is so, appears to have been first noticed by Longuet‐Higgins in a study of microseisms. Also when a sharp impedance contrast occurs in a plane‐layered model of the crust, the group velocity minimum in the fundamental mode occurs close to a period equal to four times the travel time of P ‐waves from the surface to the interface. More than one such contrast gives rise in general to more than one minimum. Similar relations hold for the higher modes.