The Anomalous Behaviour of Geomagnetic Variations of Short Period in Japan and Its Relation to the Subterranean Structure. The 7th report

The writers carried out simultaneous observations of three geomagnetic components at four stations situated in the central part of Japan. With the aid of magnetograms sent from five other magnetic observatories distributed all over Japan, analyses of various phases of a magnetic storm that occurred on March 10, 1957 are made. It is found that all the components change regularly throughout all the stations in the case of the main phase in spite of anomalous behaviour of vertical component at central Japan in the cases of SC and bay, so that it is presumed that the particular distribution of electrical conductivity which seems to play an important role for short-period variations is nearly transparent for slower variations such as Dst.南極地域観測用RMM磁力計の冬季テストをかねて,長野県細野,小諸,新潟県間瀬および神奈川県油壷に於て,地磁気3成分同時観測を行つた.この結果に女満別,女川,柿岡,下里および阿蘇観測所の観測結果を加えて,1957年3月10～11日の磁気嵐の各相について解析を行つた.磁気嵐の急始,極磁気嵐等については従来とほぼ同様な結果を得たが,主相については,短周期変化を起す地下構造の影響を受けないことをたしかめ,また内部磁場が地球の平均状態の場合にくらべて小さいことを見出した.これらの結果およびSqの解析結果にもとづいて,日本地下の電気的状態を推測した