Magnetic anomalies in Alaska

Abstract

Magnetic anomalies are the rule rather than the exception in Alaska, particularly in southeastern Alaska. Observations taken by Coast and Geodetic Survey parties indicate the presence of local disturbance all along the coast from Dixon Entrance at the southern extremity to the Bering Sea. St. George Island in the Bering Sea shows variations ranging from 6° east to 20° east, 17° east being normal.In western Alaska, on the Aleutian Peninsula, disturbances have been found, but are not fully developed. This will be done as the surveys of that area are completed. Chilkoot Inlet, southeastern Alaska, has variations ranging from 12° to 37° east, the normal being 32° east. Union Bay, southeastern Alaska, has variations ranging from 32° to 68° east, the normal being about 30°. At many places the disturbance extends out over the water‐areas in sufficient strength to affect the compasses of passing vessels. Wherever the surveys are sufficiently complete these disturbances are indicated on the navigation charts by local isogonic lines printed in red over the area affected.