Magnetic anomalies in and around Japan based on aeromagnetic surveys.

A magnetic anomaly map was complied based on the results of aeromagnetic surveys made in and around Japan, which have been in progress since 1967 under the auspices of the Geographical Survey Institute. Magnetic lineations were found in the following zones (in many cases in good correlation to the Bouguer anomaly and/or the main tectonic zones of Japan): (1) four lineation zones in the northeastern part of Japan, (2) a lineation parallel to the Kuril-Kamchatka Island Arc in the southeastern part of Hokkaido, and another one running almost perpendicularly on its northern side, (3) four lineations in the NW-SE direction over Tohoku and southwestern Hokkaido, (4) a lineation zone along the Fossa Magna tectonic line in central Honshu, (5) lineations of weak magnetic anomalies along the Median tectonic line in the northern part of Shikoku and from the region off south Shikoku to Mt. Aso, and (6) lineations in western Japan along volcanic zones such as the Hakusan and Kirishima volcanic belts.