Nearly half way to Earth's center, the boundary between the solid silicate rock mantle and the liquid iron‐alloy outer core was long thought to be a sharp discontinuity between the two vastly different regimes. Recently, detailed seismological analyses have depicted the core‐mantle boundary (CMB) as being far from simple, and in fact shows evidence for an additional thin veneer of anomalous properties in certain geographical regions. Imaged as thin as a couple of km, and up to 50‐km thick, these unique zones are characterized by strong reductions in the speeds of seismic waves relative to the overlying mantle. These areas have thus been dubbed “ultra‐low velocity zones” (ULVZs).
Seismology remains the most direct remote sensing tool for deciphering the subtleties of Earth's inaccessible deep interior. This is most commonly accomplished through the use of elastic energy that propagates away from earthquakes, traveling through the entire interior of the planet; some energy...
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Garnero, E., Thorne, M. (2007). Ulvz, Ultra‐Low Velocity Zone. In: Gubbins, D., Herrero-Bervera, E. (eds) Encyclopedia of Geomagnetism and Paleomagnetism. Springer, Dordrecht. https://doi.org/10.1007/978-1-4020-4423-6_309
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Online ISBN: 978-1-4020-4423-6