Estimate of Rayleigh-to-Love wave ratio in the secondary microseism by co-located ring laser and seismograph

Abstract

Using a co-located ring laser and an STS-2 seismograph, we estimate the ratio of Rayleigh-to-Love waves in the secondary microseism at Wettzell, Germany, for frequencies between 0.13 and 0.30 Hz. Rayleigh-wave surface acceleration was derived from the vertical component of STS-2 and Love-wave surface acceleration was derived from the ring laser. Surface wave amplitudes are comparable; near the spectral peak about 0.22 Hz, Rayleigh-wave amplitudes are about 20 percent higher than Love-wave amplitudes but outside this range, Love-wave amplitudes become higher. In terms of the kinetic energy, Rayleigh-wave energy is about 20-35 percent smaller on average than Love-wave energy. The observed secondary microseism at WET thus consists of comparable Rayleigh and Love waves but contributions from Love waves are larger. This is surprising as the only known excitation mechanism for the secondary microseism, described by Longuet-Higgins [1950], is equivalent to a vertical force and should mostly excite Rayleigh waves.

BibTeX
@article{id2084,
  author = {Tanimoto, Toshiro  and Hadziioannou, C\'eline  and Igel, Heiner  and Wassermann, Joachim  and Schreiber, Ulrich  and Gebauer, Andr\'e},
  doi = {10.1002/2015GL063637},
  journal = {Geophysical Research Letters},
  language = {en},
  title = {Estimate of Rayleigh-to-Love wave ratio in the secondary microseism by co-located ring laser and seismograph},
  year = {2015},
}
EndNote
%O Journal Article
%A Tanimoto, Toshiro 
%A Hadziioannou, Céline 
%A Igel, Heiner 
%A Wassermann, Joachim 
%A Schreiber, Ulrich 
%A Gebauer, André
%R 10.1002/2015GL063637
%J Geophysical Research Letters
%G en
%T Estimate of Rayleigh-to-Love wave ratio in the secondary microseism by co-located ring laser and seismograph
%D 2015