Hersh J. Gilbert

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[1] Investigations into mechanisms driving surface tectonics commonly search for mantle sources, but few observations constrain flow in the upper mantle and transition zone. Here variations in the upper mantle discontinuities at 410 km and 660 km below the western United States are revealed through mapping depths of compressional-to-shear wave conversions(More)
reflects two anisotropic layers, both with ␾ oriented parallel to spreading. The upper layer, above a depth of about 100 km, is dominated by spreading-induced flow, which produces no splitting near the axis, where flow is predominantly vertical, but contributes to off-axis splitting as the flow diverges to a predominantly horizontal direction. The lower(More)
Seismic data provide images of crust-mantle interactions during ongoing removal of the dense batholithic root beneath the southern Sierra Nevada mountains in California. The removal appears to have initiated between 10 and 3 Myr ago with a Rayleigh-Taylor-type instability, but with a pronounced asymmetric flow into a mantle downwelling (drip) beneath the(More)
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