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Making Love Visible in Noise: Enhanced Surface Wave Detection Using Slepian Tapers

Description: 

Seismic interferometry has become a widely adopted method for subsurface imaging across a range of spatial scales. Since its revival in the early 2000s, much research has focused on developing algorithms to compute and extract surface wave dispersion from ambient noise correlations. These algorithms typically enhance signal quality by emphasizing time-domain techniques, such as One-Bit Normalization, Frequency-Time Normalization, and Welch Waveform Stacking (Bensen et al., 2007; Seats et al., 2012; Shen et al., 2012). However, they do not address the signal quality in the frequency domain, which is crucial for enhancing surface wave detection using the spatial autocorrelation (SPAC) method first introduced by Aki in 1957. In this study, we present an algorithm for rapid computation of high-quality (low-variance) frequency-domain SPAC based on Thompson’s Multi-taper method. We calculate pairwise coherence using K-overlapping Slepian tapers that are carefully localized in both time and frequency. Preliminary results from a pair of low-quality transverse seismograms recorded in Africa demonstrate that multi-taper coherence significantly enhances the detection of Love waves and reduces uncertainty in phase and group dispersion measurements. Future work will address challenges related to memory, processing speed, and convergence when using a large number of tapers. We anticipate that this approach will enable the creation of a comprehensive high-quality catalog of short-period dispersion measurements, contributing to the refinement of global models of Earth’s crust and mantle lithosphere.

Session: Earth’s Structure from the Crust to the Core [Poster]

Type: Poster

Date: 4/16/2025

Presentation Time: 08:00 AM (local time)

Presenting Author: Sayan

Student Presenter: Yes

Invited Presentation: 

Poster Number: 107

Authors