Determining the orientations of ocean bottom seismometers using ambient noise correlation

[1] The cross-correlation of multicomponent ambient seismic noise can reveal both the velocity and polarization of surface waves propagating between pairs of stations. We explore this property to develop a novel method for determining the horizontal orientation of ocean bottom seismometers (OBS) by analyzing the polarization of Rayleigh waves retrieved from ambient noise crosscorrelation. We demonstrate that the sensor orientations can be estimated through maximizing the correlation between the radial-vertical component and the phase-shifted verticalvertical component of the empirical Green’s tensor. We apply this new method to the ELSC (Eastern Lau Spreading Center) OBS experiment data set and illustrate its robustness by comparing the obtained orientations with results from a conventional method utilizing teleseismic P and Rayleigh wave polarizations. When applied to a large OBS array, the ambient noise method provides a larger number of orientation estimates and better azimuthal coverage than typically is possible with traditional methods. Citation: Zha, Y., S. C. Webb, and W. Menke (2013), Determining the orientations of ocean bottom seismometers using ambient noise correlation, Geophys. Res. Lett., 40, doi:10.1002/grl.50698.