Single station determination of Rayleigh wave ellipticity by using the random decrement technique (RayDec)

Rayleigh wave ellipticity as a function of frequency is closely linked to underground structure, i.e., shear wave velocity profile and sediment thickness. The possibility to calculate these underground properties by inverting ellipticity curves has recently been shown. We propose a new technique enabling the Rayleigh wave ellipticity to be recovered over a wide frequency range by using ambient noise recordings. Based on the random decrement technique commonly used to characterize dynamic parameters of buildings, this method eliminates all wave types except Rayleigh waves. We apply the method to noise synthetics simulated for different underground structures and show its applicability to real seismic noise data.