@article {mark_azimuthal_2019,
	title = {Azimuthal Seismic Anisotropy of 70-Ma Pacific-Plate Upper Mantle},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {2},
	year = {2019},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB016451},
	month = {02/2019},
	pages = {1889{\textendash}1909},
	abstract = {Plate formation and evolution processes are predicted to generate upper mantle seismic anisotropy and negative vertical velocity gradients in oceanic lithosphere. However, predictions for upper mantle seismic velocity structure do not fully agree with the results of seismic experiments. The strength of anisotropy observed in the upper mantle varies widely. Further, many refraction studies observe a fast direction of anisotropy rotated several degrees with respect to the paleospreading direction, suggesting that upper mantle anisotropy records processes other than 2-D corner flow and plate-driven shear near mid-ocean ridges. We measure 6.0 {\textpm} 0.3\% anisotropy at the Moho in 70-Ma lithosphere in the central Pacific with a fast direction parallel to paleospreading, consistent with mineral alignment by 2-D mantle flow near a mid-ocean ridge. We also find an increase in the strength of anisotropy with depth, with vertical velocity gradients estimated at 0.02 km/s/km in the fast direction and 0 km/s/km in the slow direction. The increase in anisotropy with depth can be explained by mechanisms for producing anisotropy other than intrinsic effects from mineral fabric, such as aligned cracks or other structures. This measurement of seismic anisotropy and gradients reflects the effects of both plate formation and evolution processes on seismic velocity structure in mature oceanic lithosphere, and can serve as a reference for future studies to investigate the processes involved in lithospheric formation and evolution.},
	issn = {2169-9356},
	doi = {10.1029/2018JB016451},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016451},
	author = {Mark, H. F. and Lizarralde, D. and Collins, J. A. and Miller, N. C. and Hirth, G. and Gaherty, J. B. and Evans, R. L.}
}
@article {st_clair_along-strike_2016,
	title = {Along-strike structure of the Costa Rican convergent margin from seismic a refraction/reflection survey: Evidence for underplating beneath the inner forearc},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {17},
	number = {2},
	year = {2016},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2015GC006029},
	month = {02/2016},
	pages = {501{\textendash}520},
	abstract = {The convergent margin offshore Costa Rica shows evidence of subsidence due to subduction erosion along the outer forearc and relatively high rates of uplift (\~{}3{\textendash}6 mm/yr) along the coast. Recently erupted arc lavas exhibit a low 10Be signal, suggesting that although nearly the entire package of incoming sediments enters the subduction zone, very little of that material is carried directly with the downgoing Cocos plate to the magma generating depths of the mantle wedge. One mechanism that would explain both the low 10Be and the coastal uplift is the underplating of sediments, tectonically eroded material, and seamounts beneath the inner forearc. We present results of a 320 km long, trench-parallel seismic reflection and refraction study of the Costa Rican forearc. The primary observations are (1) margin perpendicular faulting of the basement, (2) thickening of the Cocos plate to the northwest, and (3) two weak bands of reflections in the multichannel seismic (MCS) reflection image with travel times similar to the top of the subducting Cocos plate. The modeled depths to these reflections are consistent with an \~{}40 km long, 1{\textendash}3 km thick region of underplated material \~{}15 km beneath some of the highest observed coastal uplift rates in Costa Rica.},
	keywords = {convergent margin, Costa Rica, subduction zone processes},
	issn = {1525-2027},
	doi = {10.1002/2015GC006029},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015GC006029},
	author = {St. Clair, J. and Holbrook, W. S. and Van Avendonk, H. J. A. and Lizarralde, D.}
}
