Variation of the angular velocity of the Earth's rotation, the oscillation of the pole and the rate of drift of the geomagnetic field and their possible association with geotectonic processes

Geophysical phenomena of annual period of variation are caused by annual fluctuation in the earth's gravitational constant. Phenomena of irregular nature, i.e., earthquake frequency, Chandler period, drift of the geomagnetic field, indicate similar fluctuation in the gravitational constant. In addition to annual and irregular fluctuations, longer cycles (thousands of millions of years) in fluctuation of gravitational constant are recognized. They cause rotational variation in core and mantle which produces the geomagnatic field and which lies at the basis of tectonic processes. Prolonged decrease or increase in gravitational constant with superposed irregular variation in gravity may correspond to periods of compression and dilatation in the Earth. — L. T. Grose.