Abstract
The supposition that spherical harmonic components of degrees 4-20 in the gravitational potential of the earth are the long wavelength spectral components of relatively sharp protrusions on nearly spherical boundaries, such as mantle phase boundaries, is examined from a statistical viewpoint. It is concluded that: 1. (1) the only important boundaries are at depth less than 1000 km; 2. (2) the two principal boundaries have a strong negative correlation, that is, highs of one correspond to lows of the other; 3. (3) the lower of the two boundaries has a greater product density contrast × r.m.s. amplitude by a factor about 1.5. The magnitudes of the undulations are consistent with narrow elevations and depressions of phase boundaries of order 100 km height in the downgoing lithospheric slabs at subduction zones.
Original language | English |
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Pages (from-to) | T1 |
Journal | Tectonophysics |
Volume | 34 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 1 Sept 1976 |