THE SIMULATION OF MAGNETIC VARIATION ANOMALIES USING SINGLE-STATION DATA

Hypothetical event maps of the vertical field derived from single-stat ion magnetic variation transfer functions are biased by the anomalous horizontal fields. An iterative scheme, proposed earlier, is used to e stimate and correct for the anomalous fields. The scheme here is appli ed to single-station transfer functions from 90 sites in southern Scot land and northern England. It converges to a stable solution in four i terations, and the results compare favourably with those predicted in the southern part of the area using measured inter-station transfer fu nctions. The resultant hypothetical event maps of the anomalous horizo ntal fields show that the Northumberland Trough and Southern Uplands c onductivity anomalies are both strikingly linear features which correl ate more closely than previously supposed with other geological and ge ophysical observations.