東アジアにおける地震活動変化の地域的特徴と関連性について
(1) 中国華北から日本海溝へいたる地域
1987 年 40 巻 3 号 p. 383-396
詳細
1987 年 40 巻 3 号 p. 383-396
Mutual relations of seismicity in the long period in various regions from North China to Japan trench in East Asia have been analyzed. Time series of events were analyzed in various regions in North China, Korean Peninsula and Japan Island.
The seismicity of each region was high in the period from 1550 to 1700. Then quiet period had been lasting until 1900. From 1900 the active period began again and have continued up to the present.
Impulsive activities were found in the western part of North China and Japan Islalds in a short time range around 1830 during the quiet period. It seems that short period variations superpose on the long period variation. These short period variations in two regions also correlated to each other.
Synchronous variations of seismicity in these regions are implicated in the formation of earthquake generating stress fields from North China to Japan trench under the common tectonic conditions. The release and the accumulation of stresses correspond to the active and quiet period of seismicity, respectively.
Correlations among seismicities and stress fields from North China to Japan trench suggest that there is a transmission of the tectonic force from the subduction of the pacific plate along the Japan trench to North China through Korean Peninsula.
