Towards Using Mermaid Waveforms in Seismic Tomography
Description:
Sparse data coverage at the global scale is one of the main challenges for improving the resolution of seismic images, specifically underneath the oceans. MERMAIDs (Mobile Earthquake Recording in Marine Areas by Independent Divers) provide new opportunities to sample the oceans in a relatively cost-effective and practical way. Our goal is to minimize the oceanic multiples in MERMAID waveforms to facilitate cross-correlation traveltime measurements and more accurate onset time readings of primarily the first arrival P waveforms. To this end, we design an Adaptive Dereverberation and Deghosting (ADD) filter and explore to what extent we can remove oceanic multiples from MERMAID waveforms using 2D spectral-element simulations. We mitigate complications in the waveforms caused by variations in bathymetry and reflection coefficients at the ocean bottom by a grid search tailored to the filter. The ADD filter successfully minimizes a finite number of multiples and redatums synthetic MERMAID waveforms to the ocean bottom for flat bathymetry. We observe that for cases with varying reflection coefficients, varying wave traveltimes, and focusing, which may arise from ocean bathymetry, the ADD filter may introduce some minor artifacts which become negligible at longer periods. After applying the ADD filter, synthetic MERMAID waveforms match those recorded at the ocean bottom well in phase, while the amplitude information may be distorted by the filter. Our synthetic tests suggest that the ADD filter is promising for removing the imprint of the ocean from MERMAID waveforms for cross-correlation traveltime measurements for seismic tomography. We will present our synthetic experiment results and discuss how to extend the ADD filter to real-data applications and incorporate MERMAID waveforms in linearized and full-waveform inversions.
Session: Earth’s Structure From the Crust to the Core [Poster]
Type: Poster
Date: 4/18/2023
Presentation Time: 08:00 AM (local time)
Presenting Author: Rachel M. Willis
Student Presenter: Yes
Invited Presentation:
Authors
Rachel Willis Presenting Author Corresponding Author rwillis1@mines.edu Colorado School of Mines |
Ebru Bozdag bozdag@mines.edu Colorado School of Mines |
Roel Snieder rsnieder@mines.edu Colorado School of Mines |
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Towards Using Mermaid Waveforms in Seismic Tomography
Category
Earth’s Structure From the Crust to the Core