Die Magnetisierung der Erde Unter den Ozeanen

Abstract

As many years must pass before the large amount of ocean data collected by the Carnegie Institution of Washington can be analyzed by the tedious method of Gauss, it seems suitable, in the meantime, to seek some other method capable of answering, to a certain extent, some of the principal geophysical questions. One such question is that pertaining to the distribution of the non‐uniform magnetization of the Earth. In a previous paper the author described a new rapid method based on the computation of Bauer's “local magnetic constant” , for a number of points distributed over the Earth's surface and investigated the law of distribution. For this investigation the magnetic results obtained at the various observatories were used. In the present paper the study is extended to the ocean areas and is based on the ocean magnetic observations obtained by the vessels operated by the Department of Terrestrial Magnetism. The method of computation is briefly described and the results of the study exhibited in a map for the epoch 1922 showing the lines of equal inhornogeneous magnetization of the Earth at intervals of 1 milligauss or 100γ, From an inspection of the map it is concluded that the distribution of the inhomogeneous magnetization over the oceans is quite systematic and not merely fortuitous and that it is not caused by the three upper kilometers (mean depth of the oceans) of the Earth's crust, having its seat principally at depths which have little to do with the surface‐distribution of land and water. The details of the magnetic situation are discussed especially in comparison with the previous chart (based on observatory data). The effect of polar movement is also considered but little weight is given it for the period in question. In connection with the question of constancy of magnetization of masses at great depths in the Earth's crust, comparisons with several recent studies of anomalies are made.