Observations of PKKP Precursors Used to Estimate Small-Scale Topography on the Core-Mantle Boundary
- 1 August 1997
- journal article
- other
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 277 (5326) , 667-670
- https://doi.org/10.1126/science.277.5326.667
Abstract
Stacks of global seismic data reveal the time and distance dependence of high-frequency (1-hertz) precursors to the seismic phasePKKP. Synthetic seismogram modeling shows that scattering from random small-scale topography at the PKKPcore-mantle–boundary reflection point generates precursory arrivals similar to those seen in the data. Models with a root mean square core-mantle–boundary topography of 250 to 350 meters and correlation length of 7 to 10 kilometers explain the main features of the data. However, a systematic range-dependent misfit between observed and predicted precursor power suggests that inner core scattering may contribute to the precursors.Keywords
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