Abstract
A systematic observation of the special astatic magnetometer in five stations will be practiced on September in 1963.
Fig. 1 shows the distribution of the observatories.
When a large earthquake within 200km from a observatory, many abnormal records might be expected before an earthquake.
But the cause has been unknown though the writer has been observed and studied for several years.
Relation between the abnormal magnetic phenomena and an earthquake will be made clear in the feature.
