Inference of core-mantle boundary topography from ISCPcPandPKPtraveltimes
نویسندگان
چکیده
منابع مشابه
Observations of PKKP Precursors Used to Estimate Small-Scale Topography on the Core-Mantle Boundary
Stacks of global seismic data reveal the time and distance dependence of high-frequency (1-hertz) precursors to the seismic phase PKKP. Synthetic seismogram modeling shows that scattering from random small-scale topography at the PKKP core-mantle–boundary reflection point generates precursory arrivals similar to those seen in the data. Models with a root mean square core-mantle–boundary topogra...
متن کاملRelationship between the viscosity and topography of the ultralow-velocity zone near the core–mantle boundary
Article history: Received 31 December 2009 Received in revised form 14 September 2010 Accepted 17 September 2010 Available online 14 October 2010
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The partial collapse of topographic structure at the core-mantle boundary (CMB) in avalanches, slumps or turbidity flows, would cause sudden temperature changes in both the upper core and the lower mantle. Although such collapses are hypothetical, it is interesting to investigate the potential consequences. Downwelling from such events could disrupt core convection cells and trigger geomagnetic...
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Extreme variations of Earth's magnetic field occurred in the Levant region around 1000 BC, when the field intensity rapidly rose and fell by a factor of 2. No coherent link currently exists between this intensity spike and the global field produced by the core geodynamo. Here we show that the Levantine spike must span >60° longitude at Earth's surface if it originates from the core-mantle bound...
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(1) Introduction.-In this paper, the values of variables at the base of the mantle and top of the core in the Earth models to be considered will be indicated by the subscripts 1 and 2, respectively; k and p will denote the incompressibility and density; let Ak = k2ki and Ap = p2 pi. In an earlier Earth model,1 Model A, k1 = 6.5 X 1012 dyn/cm2 and k2 = 6.2 X 1012 dyn/cm2, giving Ak = -0.3 X 1012...
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ژورنال
عنوان ژورنال: Geophysical Journal International
سال: 1993
ISSN: 0956-540X,1365-246X
DOI: 10.1111/j.1365-246x.1993.tb01505.x