Legal Techniques in the Determination of the Continental Shelf Outer Limits

Speaker: Prasit Aekabutra

Language: English

Place: Nan-an Building 213

Time: March, 3 2016 13.30-16.00

Professor Dr. Prasit Aekaputra is a Dean at the Faculty of Law, Huachiew Chalermprakiet University, Thailand.

Objective of this lec

ture is to provide a basic knowledge on the legal techniques in the determination of continental shelf outer limits at present day.

The concept of the continental shelf at the present is under the scientific sense. It composes continental shelf, continental slope, and continental rise according to Article 73 para 3 of LOSC.

Historical background of international law of the sea started from the concept of opened sea (mare liberum) of Hugo Grotious to closed sea(mare clausum) of John Selden.

In 1958, the result of the first UN conference on the law of the sea (UNCLOS I) caused the first conventional laws arose as follows;

1. Geneva Convention on the Territorial Sea and Contiguous Zone: CTSC

2. Geneva Convention on the Continental Shelf: CCS

3. Geneva Convention on the High Seas: CHS

4. Geneva Convention on Fishing and Conservation of the Living Resources of the High Seas: CFCLR

This convention recognizes the rights of the coastal State to claim ownership over the continental shelf adjacent to their coast. Therefore, the coastal States shall have the rights to explore and exploit all kind of natural resources in their continental shelf zone but not include the water column or the airspace over the said area. The definition of continental shelf was enacted under Article 1 of the 1958 Geneva Convention on Continental Shelf and two criterions were used. The first was depth criterion of 200 metres and the second was exploitability criterion.

Then, in 1982, the new convention, the United Nation on the Law of the Sea 1982, was adopted. The definition of the continental shelf was changed. The natural prolongation and distance criterions were used. The natural prolongation criterion has divided continental shelf into three parts; shelf, slope, and rise. The outer limit of continental shelf calls continental margin which bases on geological aspect. The natural prolongation concept bases on scientific aspect. The distance criterion 200 NM doesn’t count Article 73 para 3 of LOSC. It means that no need to find out continental margin.

In case the coastal state has continental shelf wider than 200 NM she can extends her continental shelf more than 200 NM under the provisions of Article 76 of LOSC.

1) 1% thickness compare with 100 NM (Gardiner line)

2) 60 NM from foot of slope (Hedberg line)

3) Combination method

However, Article 76 of LOSC also enshrined the maximum limits of extending her continental shelf as follows;

1) 2500 isobath + 100 NM

2) 350 NM from baseline which is measured maritime zone

3) Combination method

Submarine ridges are part of the continental shelf but not part of the continental margin. Therefore, the extent of the continental shelf is limited to 350 NM along a submarine ridge without taking consideration to the criteria under Art. 76 para 5. (See Art.76 para 6)

Submarine elevations that are natural components of the continental margin such as plateaux, rises, caps, banks and spurs. (See Art.76 para 6)

Prof. Prasit said that the extent of the continental shelf will be subject to the criteria of Art. 76 para 5 and therefore, it might be possible, in some particular cases, to extend the continental shelf more than 350 NM, if such submarine elevations are situated beyond 350 NM from the baselines but still located in the areas of 100 NM from 2,500 metres isobaths

Disputes arisen from the extended outer limits claim

1) Problem of maritime delimitation beyond 200 N.M. between the opposite coastal State and adjacent coastal State

2) Problems of the overlapping zone

Conclusion and remarks

1) 1982 Convention creates not only the obligations for the State parties but this convention recognizes as well the rights of the said States

2) By following the legal technique in the determination of the continental shelf outer limits, the coastal States may have a chance to extend their continental shelf zone more than 200 N.M.

3) There are a lot of works to do for those States who wish to extend their continental shelf outer limits.

Written by YODSAPON NITIRUCHIROT.