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Abstract We apply ambient noise tomography to a seismic array from the Trans‐Haiti project to obtain a 2‐D shear wave velocity (Vs) across Haiti. We perform multi‐component noise cross‐correlation, measure Rayleigh wave phase velocity and its horizontal‐to‐vertical amplitude ratio (H/V) between periods of 3–18 s, and jointly invert both measurements into Vs for the crustal structures of Haiti. Both H/V and phase velocity measurements exhibit consistent patterns related to the geologic units. Sedimentary basins—CSE and Plateau Central basins—show higher H/V values, while mountain areas—Massif de la Selle, Chaine des Matheux, Montagnes Noires and Massif de Nord—exhibit lower H/V. Regarding phase velocity, higher velocities are observed in northern and southern Haiti, likely reflecting the thinner crust compared to the thicker crust showing lower velocities in the central part. While our Vs model is consistent with previous model that suggested thinner crustal thickness in the northern and southern Haiti, with thickening in the center, the Moho interface in the central domain might be shallower than previously thought.
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Multimode ambient noise double-beamforming tomography with a dense linear array: revealing accretionary wedge architecture across Central Taiwan
SUMMARY Taiwan, one of the most active orogenic belts in the world, undergoes orogenic processes that can be elucidated by the doubly vergent wedge model, explaining the extensive island-wide geological deformation. To provide a clearer depiction of its cross-island orogenic architecture, we apply ambient noise tomography across an east–west linear seismic array in central Taiwan, constructing the first high-resolution 2-D shear velocity model of the upper crust in the region. We observe robust fundamental- and higher-mode Rayleigh waves, with the latter being mainly present in the western Coastal Plain. We develop a multimode double-beamforming method to determine local phase velocities across the array between 2- and 5-s periods. For each location, we jointly invert all available fundamental- and higher-mode phase velocities using a Bayesian-based inversion method to obtain a 1-D model. All 1-D models are then combined to form a final 2-D model from the surface to ∼10 km depth. Our newly developed 2-D model clearly delineates major structural boundaries and fault geometries across central Taiwan, thereby corroborating the previously proposed pro-wedge and retro-wedge models while offering insight into regional seismic hazards.
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- Award ID(s):
- 1753362
- PAR ID:
- 10535669
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Geophysical Journal International
- Volume:
- 239
- Issue:
- 1
- ISSN:
- 0956-540X
- Format(s):
- Medium: X Size: p. 467-477
- Size(s):
- p. 467-477
- Sponsoring Org:
- National Science Foundation
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