Year: 2026
Type: article
Abstract: SUMMARY Ambient noise based monitoring of subsurface velocity changes is possible without the explicit retrieval of Green’s functions by correlation. Velocity variations can directly be observed from the fluctuations in the spectrograms of ambient noise time-series or their cross-spectra. This approach is more resource efficient than the conventional Green’s function based monitoring and ideally suited for edge processing and the analysis of large volumes of data for example from fibre-optic records. The spectral fluctuations result from wave propagation in the heterogeneous subsurface and interference between different scattering paths. The fluctuations are directly related to the occurrence of coda waves in the Green’s function. In contrast to coda wave interferometry in the time domain, monitoring the evolution of spectral fluctuations allows for measurements of velocity changes that are unbiased by changes in the source spectrum. Recognizing that the imprint of the subsurface heterogeneity is directly encoded in the spectral fluctuations opens a new perspective on the investigation of subsurface scattering and attenuation.
DOI: 10.1093/gji/ggag333
Author: Christoph Sens-Schönfelder
Institution: GFZ Helmholtz Centre for Geosciences
Language: English
Topic: Seismic Waves and Analysis
Subfield: Geophysics
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,416
OpenAlex ID: W7203942126
FWCI:
Cites:
Cited by:
Related to: