Compositionally-distinct ultra-low velocity zones on Earth’s core-mantle boundary
نویسندگان
چکیده
منابع مشابه
Ultra-Low velocity zones near the core-mantle boundary from broadband PKP precursors
Short- and long-period precursors of the PKP phase were used to study an ultra-low velocity zone (ULVZ) near the core-mantle boundary beneath the Western Pacific. Synthetic seismograms were computed from a hybrid method, which handles seismic wave propagation through two-dimensional complex structures. Long-period precursors were explained by Gaussian-shaped ULVZs of 60 to 80 kilometers height ...
متن کاملTracking deep mantle reservoirs with ultra-low velocity zones
a r t i c l e i n f o Some regions of the Earth's lowermost mantle exhibit anomalous seismic properties within a thin zone, less than tens of kilometers in thickness, that directly overlies the core-mantle boundary (CMB). These regions have been dubbed Ultra-Low Velocity Zones (ULVZs) due to their greater than 10% drop in seismic velocities. High resolution seismic array studies have found smal...
متن کاملModeling the ratios of SKKS and SKS amplitudes with ultra-low velocity zones at the core-mantle boundary
[1] Between 105–115 degrees, the SKS waveform is complicated by the formation of SPdKS, a wave that has segments of P diffraction along the core mantle boundary. While previous studies have primarily focused on the moveout of SPdKS from SKS, we analyze the concomitant reduction of the SKS amplitude. Long-period SKKS/SKS amplitude ratios present a coherent global pattern. SKKS/ SKS is relatively...
متن کاملProbing an Ultra-low velocity zone at the Core Mantle Boundary with 13 and S Waves
Recent studies of the core-mantle boundary (CMB) have revealed some very anomalous tructures interpreted in terms of ultra low velocity zones (ULVZ). However, there remains considerable uncertainties about their physical descriptions or even if they occur above or below the CMB. They have only been detected in isolated situations using rather special techniques; these includes: distortions in S...
متن کاملMega ultra low velocity zone and mantle flow
Mantle flow in Earth’s interior has been inferred from a variety of geo-disciplines. Two continentalscale, nearly antipodal, large low shear velocity provinces (LLSVPs) at the base of the mantle, thought to be dense and chemically distinct likely play a significant role in mantle dynamics and plume generation, and hence are targeted in a high-resolution seismic study. We analyze broadband SPdKS...
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ژورنال
عنوان ژورنال: Nature Communications
سال: 2017
ISSN: 2041-1723
DOI: 10.1038/s41467-017-00219-x