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Excitation of microseisms
Author(s) -
Tanimoto Toshiro
Publication year - 2007
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 - 10.1029/2006gl029046
Subject(s) - microseism , buoy , geology , waves and shallow water , deep water , underwater , excitation , ocean bottom , deep sea , ocean tide , oceanography , geophysics , seismology , climatology , physics , quantum mechanics
Excitation of microseisms is generally considered to be due to pressure change at ocean bottom, for which Longuet‐Higgins derived his celebrated formula in 1950. Use of this formula is an approximation, however. Comparison with a more rigorous normal‐mode formula shows that this conventional approach is acceptable for ocean depths less than 1 km but fails in deep oceans. On the other hand, there seems to be a multitude of evidence that source region for double‐frequency microseim is near the coast and thus is generally in shallow water. An evidence from buoy data for nonlinearity in ocean waves is presented to support this view. If a source region is in shallow water, use of the Longuet‐Higgins pressure formula at ocean bottom for the excitation of microseisms is justified, although one should pay attention to ocean depths very carefully.