Open AccessSome Geophysical Implications of the Satellite‐Determined Geogravity Field
Author(s) -
Khan Mohammad Asadullah
Publication year - 1971
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1971.tb01802.x
Subject(s) - asthenosphere , geophysics , geology , earth's magnetic field , mantle (geology) , field (mathematics) , tectonics , magnetic field , seismology , subduction , physics , mathematics , quantum mechanics , pure mathematics
Summary Possible locations for the sources of the low‐degree gravity harmonics are examined in the context of the interrelationships of the geogravity field with the geomagnetic field and its drifting and non‐drifting parts as well as certain other geophysical controls. The available evidence does not support the westward drift of the gravity field. The hypothesis that the upper mantle is the most probable location for a bulk of the mass anomalies which produce the low‐degree gravity harmonics, seems to be most acceptable at this stage of our knowledge. A bulk of the mass anomalies is believed to be generated by lateral compositional and thermal variations in the asthenosphere. These variations also seem to be responsible for a major part of the observed correlation between the geogravity field and the geomagnetic secular variations by dint of their property of affecting both the density and electrical conductivity of materials. Lateral heterogeneities of the asthenosphere seem to be closely associated with relative motions in the asthenosphere and seem to play an important role in the tectonic model which explains continental drift as a result of sea‐floor spreading.