1971 年 23 巻 3-4 号 p. 295-305
Simultaneous measurements of the total geomagnetic field intensity by the same type of the proton precession magnetometers at two stations in NW Turkey have been taken cooperatively by a research group since December 1970. Up to the end of July 1971 mainly three probable local magnetic changes were observed. It was seen that after a decrease in the local field at a magnetic station (Erdek) a few earthquakes occured at either nearly N or S of that station, and after an increase in the local field an earthquake took place nearly W of the same station. In this paper the data and some results of the first part of observations are given.