Open AccessAn Analysis of Major Tectonic Features
Author(s) -
Coode A. M.
Publication year - 1966
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1966.tb03101.x
Subject(s) - tectonics , geology , convection , degree (music) , symmetry (geometry) , seismology , series (stratigraphy) , geophysics , geodesy , geometry , paleontology , mechanics , physics , mathematics , acoustics
Summary The major tectonic features, such as mountain systems, trenches and oceanic ridges, may be regarded as linear. Their generating forces may be approximated by lines of δ‐functions and expressed analytically by a spherical harmonic series to the twelfth degree. Separate analyses of the different features indicate that there was a fourth degree symmetry in the past (from aseismic, or passive, ridges) and a fifth degree symmetry in the present‐from an analysis of seismically active ridges and a combination of all the major tectonic features. Two points emerge. First, if the subcrustal shears are proportional to the velocities of the convection cells then one can obtain the distribution of global tectonic forces and the flow patterns from the same source. Secondly, the convection cell pattern has recently changed its dominant mode from fourth to fifth degree.