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Estimate of Rayleigh‐to‐Love wave ratio in the secondary microseism by a small array at Piñon Flat observatory, California
Author(s) -
Tanimoto Toshiro,
Lin ChinJen,
Hadziioannou Céline,
Igel Heiner,
Ver Frank
Publication year - 2016
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 - 10.1002/2016gl071133
Subject(s) - microseism , rayleigh wave , equipartition theorem , seismometer , seismogram , love wave , seismology , rayleigh scattering , energy (signal processing) , geology , physics , surface wave , mechanical wave , wave propagation , optics , longitudinal wave , magnetic field , quantum mechanics
Using closely located seismographs at Piñon Flat (PFO), California, for 1 year long record (2015), we estimated the Rayleigh‐to‐Love wave energy ratio in the secondary microseism (0.1–0.35 Hz) in four seasons. Rayleigh wave energy was estimated from a vertical component seismograph. Love wave energy was estimated from rotation seismograms that were derived from a small array at PFO. Derived ratios are 2–2.5, meaning that there is 2–2.5 times more Rayleigh wave energy than Love wave energy at PFO. In our previous study at Wettzell, Germany, this ratio was 0.9–1.0, indicating comparable energy between Rayleigh waves and Love waves. This difference suggests that the Rayleigh‐to‐Love wave ratios in the secondary microseism may differ greatly from region to region. It also implies that an assumption of the diffuse wavefield is not likely to be valid for this low frequency range as the equipartition of energy should make this ratio much closer.