Although it was stronger than any earthquake in the continental United States since the Great San Francisco earthquake of 1906 (magnitude 7.8), it was modest by Indonesian standards.
The earthquake as scientists upon my surface understand is due to the movements of the plates of continental shelves over and under one another.
地震照地表科学家的理解，是由于大陆架板块彼此挤压碰撞而形成的。
3
As lower Yangtze is the continental edge-extending area controlled by asthenolith through a long time of the research on geology of the depth, lower Yangtze area has general background of earthquake.