Abstract
Data observed by the extensometers installed at the OGA and the NIBETU stations of the Akita Geophysical Observotary for the period of 1967 to 1975 are analyzed. The distance between the stations is apart about 39 km and a comparative study for the ground strain is performed. Short and long period strain characteristics are clarified using Chebychev function technique. It is found that the areal strain variations for both the stations are similar and variations of the maximum shear strain at the NIBETU station appears 2.5 years faster than those at the OGA station. An anomalous strain change at the end of 1973, recorded at many crustal movement observatories in Japan, was also observed by both the stations. It is noted that comparisons of the principal strains with data obtained from seismic and geodetic methods show good agreement.
