HR: 17:00h
AN: S34A-05    [Abstracts]
TI: Excitation of Long Period Rayleigh Waves by Large Storms in the North Atlantic Ocean
AU: * Kurrle, D
EM: kurrle@geophys.uni-stuttgart.de
AF: Institute of Geophysics, University of Stuttgart, Azenbergstrasse 16, Stuttgart, D-70174, Germany
AU: Widmer-Schnidrig, R
EM: widmer@geophys.uni-stuttgart.de
AF: Institute of Geophysics, University of Stuttgart, Azenbergstrasse 16, Stuttgart, D-70174, Germany
AU: Widmer-Schnidrig, R
EM: widmer@geophys.uni-stuttgart.de
AF: Black Forest Observatory (BFO), Research Facility of the Universities of Karlsruhe and Stuttgart, Heubach 206, Wolfach, D-77709, Germany
AB: Ten years after the discovery of the continuous excitation of the Earth's free oscillations (Nawa et al. 1998), often referred to as the hum of the Earth, the sources of this excitation are still under debate. Recent studies suppose that the Earth's hum is caused either by atmospheric turbulence or by infragravity waves in the oceans. While under normal conditions, it is not possible to identify 'hum events', Rhie and Romanowicz (2006) showed that large storms over the Northern Pacific ocean with high waveheights are able to produce long period (T>100 sec) Rayleigh waves when they reach the west coast of North America. These Rayleigh waves can be detected using broadband seismic networks as arrays. We recently demonstrated the suitability of the German Regional Seismic Network (GRSN) for array studies of the long period seismic background (Kurrle and Widmer-Schnidrig 2006). We focus on these data to provide further evidence for the capability of ocean storms to cause seismic waves at periods T>100 sec. Several storms in the Atlantic Ocean are examined, and data from the GRSN and the Berkeley Digital Seismic Network (BDSN) are used to infer the source regions of the seismic waves. Comparison of the seismic results with global waveheight distributions from Wave Watch 3 nowcasts, provided by the Fleet Numerical Meteorology and Oceanography Center (FNMOC), reveal the direct connection between the storms and the seismic waves.
DE: 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762, 1218, 3319, 4550)
DE: 7255 Surface waves and free oscillations
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Seismology [S]
MN: 2007 Fall Meeting