@article {liu_seismic_2024,
	title = {Seismic Azimuthal Anisotropy Beneath the Alaska Subduction Zone},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {14},
	year = {2024},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL109758},
	month = {07/2024},
	pages = {e2024GL109758},
	abstract = {We estimate depth-dependent azimuthal anisotropy and shear wave velocity structure beneath the Alaska subduction zone by the inversion of a new Rayleigh wave dispersion dataset from 8 to 85 s period. We present a layered azimuthal anisotropy model from the forearc region offshore to the subduction zone onshore. In the forearc crust, we find a trench-parallel pattern in the Semidi and Kodiak segments, while a trench-oblique pattern is observed in the Shumagins segment. These fast directions agree well with the orientations of local faults. Within the subducted slab, a dichotomous pattern of anisotropy fast axes is observed along the trench, which is consistent with the orientation of fossil anisotropy generated at the mid-ocean ridges of the Pacific-Vancouver and Kula-Pacific plates that is preserved during subduction. Beneath the subducted slab, a trench-parallel pattern is observed near the trench, which may indicate the direction of mantle flow.},
	keywords = {Alaska subduction zone, aleutian subduction zone, azimuthal anisotropy, seismic anisotropy, surface wave, surface wave tomography},
	issn = {1944-8007},
	doi = {10.1029/2024GL109758},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024GL109758},
	author = {Liu, Chuanming and Sheehan, Anne F. and Ritzwoller, Michael H.}
}
@article {liu_seismic_2024,
	title = {Seismic Azimuthal Anisotropy Within the Juan de Fuca - Gorda Plate System},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {22},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL111835},
	pages = {e2024GL111835},
	abstract = {Abstract We estimate seismic azimuthal anisotropy for the Juan de Fuca - Gorda plates from inversion of a new 10{\textendash}80 s period Rayleigh wave dataset, resulting in a two-layer model to 80 km depth. In the lithosphere, most anisotropy patterns reflect the kinematics of plate formation, as approximated from seafloor-age-based paleo-spreading, except for regions close to propagator wakes and near plate boundaries. In the asthenosphere, the fast propagation orientations align with convective shear as inferred from the NUVEL1A plate motion model, which is indicative of a \~{}3 Myr average, rather than with the more recent, \~{}0.8 Myr, motions inferred from MORVEL. Regional anisotropy of this young plate system thus records convection like older plates such as the Pacific. On smaller scales, anisotropy imaging provides insights into dynamics of plate generation and can further elucidate plate reorganizations and changes in boundary loading.},
	keywords = {juan de fuca plate, oceanic lithosphere, seismic aniostropy, seismic tomography, surface wave tomography},
	doi = {https://doi.org/10.1029/2024GL111835},
	author = {Liu, Chuanming and Becker, Thorsten and Wu, Mengyu and Han, Shuoshuo and Ritzwoller, Michael H.}
}
@article {harmon_evolution_2020,
	title = {Evolution of the Oceanic Lithosphere in the Equatorial Atlantic From Rayleigh Wave Tomography, Evidence for Small-Scale Convection From the PI-LAB Experiment},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {21},
	number = {9},
	year = {2020},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC009174},
	month = {08/2020},
	pages = {e2020GC009174},
	abstract = {The oceanic lithosphere is a primary component of the plate tectonic system, yet its evolution and its asthenospheric interaction have rarely been quantified by in situ imaging at slow spreading systems. We use Rayleigh wave tomography from noise and teleseismic surface waves to image the shear wave velocity structure of the oceanic lithosphere-asthenosphere system from 0 to 80 My at the equatorial Mid-Atlantic Ridge using data from the Passive Imaging of the Lithosphere-Asthenosphere Boundary (PI-LAB) experiment. We observe fast lithosphere (VSV > 4.4 km/s) that thickens from 20{\textendash}30 km near the ridge axis to 70 km at seafloor >60 My. We observe several punctuated slow velocity anomalies (VSV < 4.1 km/s) in the asthenosphere between 50 and 150 km depth, not necessarily focused beneath the ridge axis. Some of the slow velocity regions are located within 100 km of the ridge axis, but other slow velocity regions are observed at distances > 400 km from the ridge. We observe a high velocity lithospheric downwelling drip beneath 30 My seafloor that extends to 80{\textendash}130 km depth. The asthenospheric slow velocities likely require partial melt. Although melt is present off axis, the lack of off-axis volcanism suggests the lithosphere acts as a permeability boundary for deeper melts. The punctuated and off-axis character of the asthenospheric anomalies and lithospheric drip suggests small-scale convection is active at a range of seafloor ages. Small-scale convection and/or more complex mantle flow may be aided by the presence of large offset fracture zones and/or the presence of melt and its associated low-viscosities and enhanced buoyancies.},
	keywords = {asthenosphere, Atlantic Ocean, oceanic lithosphere, PI-LAB, shear velocity, surface wave tomography},
	issn = {1525-2027},
	doi = {10.1029/2020GC009174},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GC009174},
	author = {Harmon, Nicholas and Rychert, Catherine A. and Kendall, J. Michael and Agius, Matthew and Bogiatzis, Petros and Tharimena, Saikiran}
}
@article {miller_upper_2009,
	title = {Upper mantle structure beneath the Caribbean-South American plate boundary from surface wave tomography},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {114},
	number = {B1},
	year = {2009},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2007JB005507},
	abstract = {We have measured shear wave velocity structure of the crust and upper mantle of the Caribbean-South American boundary region by analysis of fundamental mode Rayleigh waves in the 20- to 100-s period band recorded at the BOLIVAR/GEODINOS stations from 2003 to 2005. The model shows lateral variations that primarily correspond to tectonic provinces and boundaries. A clear linear velocity change parallels the plate bounding dextral strike-slip fault system along the northern coast of Venezuela, illustrating the differences between the South American continental lithosphere, the Venezuelan archipelago, and the Caribbean oceanic lithosphere. At depths up to 120 km beneath the Venezuelan Andes and the Maracaibo block, there is evidence of underthrusting of the Caribbean plate, but there is no other evidence of subduction of the Caribbean plate beneath the South American plate. In eastern Venezuela, linear crustal low velocities are associated with the fold and thrust belts whereas as higher crustal velocities are imaged in the Guayana shield lithosphere. The subducting oceanic part of the South American plate is imaged beneath the Antilles arc. The surface wave images combined with seismicity data suggest shear tearing of the oceanic lithosphere away from the buoyant continental South American plate offshore of northeastern Venezuela. The continental lithosphere south of the slab tear is bent down toward the plate boundary in response to the propagating tear in the lithosphere. We interpret a nearly vertical low-velocity {\textquotedblleft}column{\textquotedblright} west of the tear centered beneath the Cariaco Basin, with three-dimensional asthenospheric flow around the southern edge of the subducting oceanic lithosphere, with the asthenosphere escaping from beneath continental South America and rising into the plate boundary zone. The complex plate boundary structure is best examined in three dimensions. We discuss the new surface wave tomographic inversion in the context of results from other researchers including local seismicity, teleseismic shear wave splits, and interpretations from active source profiling.},
	keywords = {plate boundary, surface wave tomography, upper mantle structure},
	issn = {2156-2202},
	doi = {10.1029/2007JB005507},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2007JB005507},
	author = {Miller, Meghan S. and Levander, Alan and Niu, Fenglin and Li, Aibing}
}
