Abstract
High-precision simultaneous observations of the geomagnetic field have been made over areas with fault displacements and junctions of mountain structures in Tajikistan using proton magnetometers MPP-1 with 0.1γ sensitivity. The optimal duration and frequency of resurveying as well as the detection level of possible tectonomagnetic variations (0.6γ) have been experimentally determined.
Examples of characteristic local geomagnetic variations possibly associated with changes of tectonic stresses are given. Oscillations with periods of one or a few weeks and amplitudes of 0.7-1.5γ occur during seismically quiet times, and monotonic variations continuing over a month with subsequent change of sign and a tendency for rapid recovery to the former level occur shortly before energy class K>11 earthquakes (on the Rautian scale, where K=1.8ML+4).
