z-logo
Premium
Background Love and Rayleigh waves simultaneously generated at the Pacific Ocean floors
Author(s) -
Nishida Kiwamu,
Kawakatsu Hitoshi,
Fukao Yoshio,
Obara Kazushige
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl034753
Subject(s) - rayleigh wave , love wave , geology , microseism , infragravity wave , geophysics , seismology , atmospheric wave , wind wave , rayleigh scattering , gravity wave , shear waves , shear (geology) , geodesy , surface wave , wave propagation , mechanical wave , longitudinal wave , physics , oceanography , optics , petrology
Earth's background free oscillations known as Earth's hum have been interpreted as the Earth response to vertical pressure loads due to atmospheric and/or oceanic disturbances. Such excitation mechanisms, however, can hardly excite Love waves. Here we show clear evidence of background Love waves from 0.01 to 0.1 Hz, based on the array analysis of tiltmeters in the Japanese islands. The observed kinetic energy of Love waves is as large as that of Rayleigh waves through the whole period of analysis. The predominant incident azimuths are common to the Love and Rayleigh waves, the strongest in directions along ocean‐continent borders, next from deep ocean floors and the weakest from continents. These observations indicate that background Love and Rayleigh waves are largely generated by the same mechanisms other than vertical pressure loading. We suggest that the most likely excitation source is shear traction acting on a sea‐bottom horizon due to linear topographic coupling of infragravity waves.

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here