Fig. 1
From: Potential utility of geomagnetic data for geolocation of demersal fishes in the North Pacific Ocean
Magnetic field values in Alaska, USA. a The main field at sea surface elevation modeled by International Geographic Reference Field (IGRF) increases from the southwest to the northeast (contour lines of 500 nT are shown). Four magnetic observatories in Alaska (see Fig. 2) are indicated by yellow crosses. b Magnetic field anomalies (red represents large positive anomalies, blue represents large negative anomalies, and green represents non-anomaly areas) occur throughout the region. Information on anomaly magnitude is available from a map with 1-km resolution by the North American Magnetic Anomaly Group (NAMAG). Numbered areas identify characteristics of the anomaly map referred to in the discussion