Observation of Geomagnetic and Geoelectric Variations in the Eastern Part of Hokkaido
Mori, T.
Abstract
Field observations of the variations of geomagnetic three components were made at several stations in the eastern part of Hokkaido, with a classical type portable magnetometer or a flux-gate type GIT-magnetometer. Earth currents were also observed at several stations, some of which are the same as the geomagnetic observation.
From the magnetograms and the earth-current records, geomagnetic and geoelectric bay and bay-like variations were selected, and relations among the geomagnetic three components and those between geomagnetic horizontal vector and earth-current vector were studied.
Parkinson vectors in the eastern part of Hokkaido are not so large (√(A2+ B2) < 0.5) as the central Japan anomaly. The vectors [point nearly to the east] on the line which connects Memambetsu and Nemuro and gradually tend toward the south-west as the observation station goes away toward the west from Nemuro along the coast of the Pacific Ocean. And the vector at Kamichanbetsu in the Konsen Plane is nearly zero.
At the coastal stations of the Pacific Ocean, which are in the area of high positive Bouguer anomaly, amplitude of earth-current potential variations are very large (E/H = 3〜5 mV/km/γ) and the dircctions are very steady. On the other hand, at the stations in the Konsen Plane where the thickness of Cainozoic deposits is estimated at about 1500m, the amplitude are very small (E/ H = 0.3〜0.5 mV / km /γ) and the directions are unstable.
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