|Title||Estimate of Rayleigh-to-Love wave ratio in the secondary microseism by a small array at Piñon Flat observatory, California|
|Publication Type||Journal Article|
|Year of Publication||2016|
|Authors||Tanimoto T, Lin C-J, Hadziioannou C, Igel H, Vernon F|
|Journal||Geophysical Research Letters|
|Keywords||7255 Surface waves and free oscillations; 7294 Seismic instruments and networks; 7299 General or miscellaneous; Rayleigh-to-Love wave ratio in microseism|
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.