A maritime dispute surrounding Ieodo, a submerged rock in the East China Sea, has resurfaced as China incorporated it last week in its air defense zone without consultation with South Korea.

The renewed dispute has also revealed that despite its claim to the rock, Seoul has not included Ieodo in its own air defense identification zone, although China and Japan have put it under their respective zones.

Seoul maintains it cannot recognize China’s ADIZ, while expressing regrets over the unilateral declaration of the zone.

Internationally called Socotra Rock, Ieodo has long been a source of tension between South Korea and China, as it is located within the overlapping exclusive economic zones of the two countries.

Seoul says it is within its EEZ, given that it is located 149 kilometers southwest of Korea’s southernmost island of Marado, while China’s nearest island of Yushandao is 287 kilometers away.

Under U.N. maritime law, a reef cannot be a subject of territorial dispute. But Seoul believes that the rock belongs to it as the reef and its adjoining waters are part of its continental shelf.

Seoul and Beijing have had several negotiations regarding the EEZ, but no clear agreement has been reached. Seoul has demanded that the EEZ be demarcated by drawing a median line, while Beijing argues that the coasts and the population along them must be taken into account in EEZ demarcation.

The rock currently serves as the foundation for the Ocean Research Station, which was built in 2003 by the Korean government to measure ocean currents and accumulate data for weather forecasting, fishery and environmental protection and prevention of natural disasters such as tidal waves and tropical storms.

The long-simmering dispute over Ieodo was rekindled last year as well after a Chinese senior official was reported to have renewed a jurisdictional claim to it. The official was said to have claimed that Ieodo would be included in areas subject to China’s surveillance and patrol.

The dispute with China has strengthened the rationale for the Seoul government to establish a strategic naval base on Jejudo Island. The base is to be completed by the end of 2015.

If a dispute over Ieodo were to erupt, a warship could reach it from a Busan port in about 21 hours, but in some eight hours from the Jeju base.

By Song Sang-ho (sshluck@heraldcorp.com)