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WITHDRAWN Direct Inversion of Ambient Noise Multi-Modal Surface Wave Dispersions for 3D Velocity Structures

Description: 

WITHDRAWN Ambient noise-based surface wave tomography of subsurface structures ranging from shallow sediments to the upper mantle has been carried out in various regions, which is crucial for understanding regional tectonic evolution and seismic hazard mitigation. Surface wave dispersions can be extracted by either the conventional two-station method or the recently developed array-based method. Yet, both encounter certain inherent limitations: the two-station method cannot extract high-mode surface-wave dispersion, while array-based methods have relatively low spatial resolution. In this study, we introduce a novel direct inversion scheme of ambient noise multi-modal surface wave dispersions. First, we calculate cross-correlations among all station pairs in a dense array following the standard ambient noise data processing workflow. Then, we apply the array-based Frequency-Bessel transformation to calculate multi-modal dispersion spectra for cross-correlation functions from station pairs distributed along the same line. Multi-modal dispersion data can be picked using an artificial neural network. Finally, we iteratively update the 3D velocity model by fitting the multi-modal dispersion data with theoretical predictions from the model. We validate our new method using data from a dense array in Southern Yunnan, China. We obtain a high-resolution velocity model of the study region, which aligns well with known geological structures. Our new method can potentially be applied to other regions with dense arrays for subsurface structural imaging.

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

Type: Poster

Date: 5/2/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Gongheng

Student Presenter: No

Invited Presentation: 

Authors