Excitation of microseisms
Article first published online: 13 MAR 2007
Copyright 2007 by the American Geophysical Union.
Geophysical Research Letters
Volume 34, Issue 5, March 2007
How to Cite
2007), Excitation of microseisms, Geophys. Res. Lett., 34, L05308, doi:10.1029/2006GL029046.(
- Issue published online: 13 MAR 2007
- Article first published online: 13 MAR 2007
- Manuscript Accepted: 7 FEB 2007
- Manuscript Revised: 1 FEB 2007
- Manuscript Received: 8 DEC 2006
- seismic noise;
- normal mode
 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.