Regional Crustal Imaging by Inversion of Multimode Rayleigh Wave Dispersion Curves Measured From Seismic Noise: Application to the Basque‐Cantabrian Zone (N Spain)

Abstract

Seismic-noise tomography is routinely applied for imaging geological structures at different spatial scales. The frequently used time-domain approach presents two limitations. First, extracting surface-wave group velocities from time-domain cross-correlations requires interstation distances of at least three wavelengths, which may be problematic when working at local or regional scales. Second, the presence of higher modes of surface waves in the cross-correlation functions is often disregarded, which may cause loss of valuable information about the shear-wave velocity structure. In this work, we present a complete inversion scheme that avoids these limitations and use it to obtain a 3D shear-wave velocity model of the Basque-Cantabrian Zone (N Spain), a structurally complex area affected by multiple tectonic events. The resulting model agrees with the existing geological and geophysical knowledge and significantly extends the area for which high-resolution information is available.

Spatial variability of shear wave velocity: implications for the liquefaction response of a case study from the 2010 Maule Mw 8.8 Earthquake, Chile

“…It is clear from these equations that the relationship between the data and the phase velocity is nonlinear. Still, the dispersion curve c(ω) can be retrieved through the zero-crossings (Ekström et al, 2009;Ekström, 2014) or by fitting a Bessel function to the CC waveform (e.g., Menke and Jin, 2015;Pilz et al, 2017;Olivar-Castaño et al, 2020).…”

A High‐Resolution Shear Velocity Model of the Crust and Uppermost Mantle Beneath Westernmost Mediterranean Including Radial Anisotropy

“…The presence of radial anisotropy has been discussed in some regional surface wave tomographic models (e.g., Boschi et al, 2009;Schivardi & Morelli, 2011) but, as for the full waveform cases discussed below, their large spatial scale, involving at least the whole Mediterranean basin, makes difficult to discuss in detail the radial anisotropy variations beneath the Iberian Peninsula. A couple of surface wave tomographic models of northern Iberia obtained from ambient noise have been recently published (Acevedo et al, 2019(Acevedo et al, , 2022Olivar-Castaño et al, 2020)., one of them accounting for radial anisotropy (Acevedo et al, 2022). However, their data only make it possible to model the crust, with the discussion on the presence of radial anisotropy limited to depths of 10-15 km.…”

Towards a Digital Twin of the Earth System: Geo-Soft-CoRe, a Geoscientific Software & Code Repository

“…The different strategies to image and constrain the structure of the lithosphere require a deep understanding of wave propagation mechanisms and seismic sources. In principle, we can use the seismic wavefield generated by any source to study the structure of the lithosphere (Dias et al, 2015;Haned et al, 2016;Corela et al, 2017;Poveda et al, 2018;Romero and Schimmel, 2018;Andrés et al, 2020;Nuñez et al, 2020;Olivar-Castaño et al, 2020;Ayarza et al, 2021) and to monitor natural and anthropogenic activity (Díaz et al, 2017;Lecocq et al, 2020;Díaz et al, 2022). In that respect, the use of seismic noise is progressively gaining more importance in Earth science (Campillo and Roux, 2015;Maciel et al, 2021) as it is ubiquitous in time and space (Stutzmann et al, 2009;Schimmel et al, 2011a).…”