Mapping the Lithosphere and Asthenosphere Beneath Alaska With Sp Converted Waves
نویسندگان
چکیده
We obtained a 3D image of crust and mantle seismic velocity gradients beneath the state Alaska using common-conversion point (CCP) stacking S-to-p converted body waves recorded by hundreds stations from NSF EarthScope Transportable Array other portable arrays permanent networks. Moho depths delineate thick underthrust Yakutat terrane crustal root Brooks Range. The North American lithosphere is particularly thin close to subducting in subduction zone, consistent with thinning upper plate zone flow melt rising wedge. remains relatively far northwest north, including Seward Peninsula regions south Range where lithospheric extension foundering may have played role. dramatically thickens northern Arctic it appears be both cold highly viscous. CCP stack also revealed pronounced positive gradient at 130–230 km that represents base layer within asthenosphere whose low velocities are best explained presence partial melt. Although this present lithosphere, melting enabled slab-derived fluids, strongest northeast Wrangell volcanic field, suggesting kilometers away slab, likely due decompression upwelling asthenosphere.
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ژورنال
عنوان ژورنال: Geochemistry Geophysics Geosystems
سال: 2022
ISSN: ['1525-2027']
DOI: https://doi.org/10.1029/2022gc010517