Secular Variation Anomalies and Aseismic Geodynamic in the Urals [chapter]

V. A. Shapiro, A. L. Aleinikov, A. A. Nulman, V. A. Pyankov, A. V. Zubkov
1979 Tectonomagnetics and Local Geomagnetic Field Variations  
Secular variation anomalies (SVA) of two types were revealed as a result of high-precision measurements of the geomagnetic field in the Urals. The results suggest significantly non-uniform tectonic stresses in the Urals. An attempt to measure the time dependence of stress variations was made. An anomaly of the first type is characterized by the steady growth of the field at a rate of 2-3 nT/year. Laboratory experiments with the rocks showed that similar changes might be caused by the changes of
more » ... d by the changes of magnetic susceptibility and remanent magnetization with changes of hydrostatic pressure of about 10 bars. The anomalies of second type border the zone of folded Urals to the East and the West. They exhibit sign changes in trends of up to 20 nT/year. These anomalies are probably caused by the change of the rock conductivity because of changes in pore pressure in the zones of thrusting.
doi:10.1007/978-94-010-9825-0_4 fatcat:maslzw6t75entozk7l53mh3bvi