Abstract
Long-term precise magnetic observations are being carried out at the Eilat test site as a part of active tectonic fault multi-sensor geophysical monitoring. The gradiometer system comprises three highly sensitive potassium total field sensors with short bases - up to 50 m. The gradiometer time series contain residuals of external magnetic field variations, which are essentially homogeneous over such short distances. Mutual regression analysis of the gradiometer and the vector magnetometer time series was proved to be an effective tool in reduction of the influence of external homogeneous variation on gradiometer readings. Monitoring results together with time dependence of regression coefficients are analyzed.