日本是个多地震多火山的岛国,属太平洋西岸火山地震带的一部分。每年发生在陆地及其周边海域的地震数以千计。历史上不知有多少次地震、海啸使日本人民的生命财产遭受惨重损失。因此,日本政府历来重视地震的研究与预报工作。位于日本伊豆半岛的东海域的浅海区(简称伊东 Japan is a multi-volcano earthquake island nation, part of the Pacific West Bank volcanic belt. Thousands of earthquakes occur each year on land and in the surrounding waters. I do not know how many earthquakes happened in history, and the tsunami caused heavy losses to the lives and property of the Japanese people. Therefore, the Japanese government has always attached importance to earthquake research and forecasting work. Located in the shallow sea of ​​the East China Sea in Izu Peninsula, Japan (Ito for short)