ConstrainingS-wave velocity using Rayleigh wave ellipticity from polarization analysis of seismic noise

Abstract

We develop a new method for measuring ellipticity of Rayleigh waves from ambient noise records by degree-of-polarization (DOP) analysis. The new method, named DOPE , shows a good capability to retrieve accurate ellipticity curves separated from incoherent noise. In order to validate the method we perform synthetic tests simulating noise in a 1-D earth model. We also perform measurements on real data from Antarctica and Northern Italy. Observed curves show a good fit with measurements from earthquake records and with theoretical ellipticity curves. The inversion of real data measurements for v S structure shows a good agreement with previous models. In particular, the shear-wave structure beneath Concordia station shows no evidence of a significant layer of liquid water at the base of the ice. The new method can be used to measure ellipticity at high frequency and therefore it will allow the imaging of near-surface structure, and possibly of temporal changes in subsurface properties. It promises to be useful to study near-surface processes in a wide range of geological settings, such as volcanoes, fault zones and glaciers.

Crustal structure of the Azores Archipelago from Rayleigh wave ellipticity data

“…These long-period RWE measurements are sensitive to deeper crustal structure (e.g. Berbellini et al 2019) and, thus, the good agreement of RWE predictions based on different types of models gives confidence on the robustness of the deeper crustal structure obtained from our RWE inversions. The model Spieker-M7c fits the CMLA data slightly better than Spieker-M7a, which is somewhat surprising, given that it was built using data from station ROSA in São Jorge Island rather than from CMLA in São Miguel.…”

“…Future work using RWE measurements from seismic ambient noise data going down to shorter wave periods should enable us to obtain further detailed models of the shallow crust in the region (e.g. Hobiger et al 2013;Berbellini et al 2019), which are important to improve seismic hazard assessments.…”

The Polarization of Ambient Noise on Mars

“…The origin of these local effects was extensively studied and modeled prior the mission launch and might be related to pressure ground deformation (Lognonné & Mosser, 1993), thermal effects (Van Hoolst et al, 2003), lander induced noise (Murdoch et al, 2017) as reviewed by Mimoun et al (2017). If Mars seismic noise contains propagating waves, the noise might be useful for imaging the planet interior, from local scale (Romero & Schimmel, 2018;Berbellini et al, 2019), to global scale (Schimmel et al, 2011a;Nishikawa et al, 2019).…”

“…(2017). If Mars seismic noise contains propagating waves, the noise might be useful for imaging the planet interior, from local scale (Berbellini et al., 2019; Romero & Schimmel, 2018), to global scale (Nishikawa et al., 2019; Schimmel, Stutzmann, & Gallart, 2011).…”

The Polarization of Ambient Noise on Mars 

“…The origin of these local effects was extensively studied and modeled prior the mission launch and might be related to pressure ground deformation (Lognonné & Mosser, 1993), thermal effects (Van Hoolst et al, 2003), lander induced noise (Murdoch et al, 2017) as reviewed by Mimoun et al (2017). If Mars seismic noise contains propagating waves, the noise might be useful for imaging the planet interior, from local scale (Berbellini et al, 2019;Romero & Schimmel, 2018), to global scale (Nishikawa et al, 2019;.…”