Japan Coast Guard will gather data in the East China Sea
In response to China’ one-sided claim to an extended continental shelf in the East China Sea, the Japan Coast Guard (JCG) has started from fiscal 2018 operating two large-size survey ships equipped with high performance depth sounders for shallow seas to prepare data on submarine topography, which will be used to disprove China’s claim, Sankei Shimbun learned on June 16. The JCG also introduced autonomous underwater vehicles equipped with the same type of depth sounder. If China’s claim to an extended continental shelf is internationally recognized, Japan would lose its administrative right to seabed resources, so the JCG will hurriedly gather and analyze precise data in waters around the shallow Okinawa Trough.
Operating high performance depth sounders
While Japan argues that the crust form the Chinese Continent in the East China Sea is uninterrupted so there is no basis for extending the continental shelf, China claims that the crust is interrupted at the Okinawa Trough due to the oceanic crust such as magma, so the country can claim to extend the continental shelf.
China has submitted its data on submarine topography to an international committee, but the examination by the committee was suspended on account of Japan’s opposition. However, “it is unpredictable when and how China will take the next step to call for restarting the examination,” according to a source connected to the Japanese government, so the JCG’s data gathering is in preparation for an unexpected situation in the future for Japan to respond swiftly.
China, aiming to build a “strong maritime nation,” claims that its continental shelf should be extended to areas around the Okinawa Trough, about 150 nautical miles (278 km) toward the Japanese side from the Japan-China geographical dividing line in the East China Sea. The PRC apparently aims to expand the range of natural resources development.
The deepest point of the Okinawa Trough is about 2,300 meters but areas around the deepest point suddenly become shallow. The JCG utilizes its depth sounders for shallow seas in waters between the dividing line and the Okinawa Trough where the depth is below 200 meters. (Abridged)