Lecture on the Extension of the Outer Limits of the Continental Shelf under UNCLOS Article 76: the Case of New Zealand's Submission



In accordance with the United Nations Convention on the Law of the Sea (UNCLOS), Coastal States can extend their continental shelf beyond 200 nautical miles if the outer edge of the continental margin extends beyond that distance. Coastal States shall submit scientific information on the limits of the continental shelf to the Commission on the Limits of the Continental Shelf (CLCS).
Eleven coastal States submitted to the CLCS by June 2008, i.e., the Russian Federation, Brazil, Australia, Ireland, New Zealand, Norway, France, Mexico, Barbados, the United Kingdom and Indonesia. Joint submission has been made by France, Ireland, Spain and the United Kingdom. Many coastal States, including Japan, have been paying much attention to the consideration given by the CLCS to these submissions.
On the occasion of Mr. Ray Wood's visit to Japan, he gave the lecture, "On the Extension of the Outer Limits of the Continental Shelf under UNCLOS Article 76: the Case of New Zealand's Submission. EMr. Wood, who leads the Ocean Exploration Section of the Institute of Geological and Nuclear Sciences, has participated in New Zealand's Continental Shelf Project, which was established for the purpose of submitting scientific and technical information to the CLCS. Mr. Wood explained how the project has progressed for the submission as well as the unique features of the sea bottom around his country. After the lecture, a question and answer session was provided and lively discussion was held.

Summary of the program

Date: 14:30pm  E16:10pm, Friday, July 25, 2008
Venue: 10th Floor, Kaiyo Senpaku Building, 1-15-16 Toranomon, Minato-ku, Tokyo
Organized by: Ocean Policy Research Foundation
Sponsored by: The Nippon Foundation
Participants: Approximately 80 persons
Summary of the lecture

(1) The process of the submission by New Zealand to the CLCS
Just after the ratification of UNCLOS in 1996, New Zealand launched the Continental Shelf Project for the purpose of submitting scientific and technical information to the CLCS. Following the analytical studies to review existing data, surveys were carried out to collect further necessary data and they were completed by 2002. Four years were required to analyze the data and to prepare the documents for submission. At the same time, negotiations were being carried out with Australia on maritime delimitation.
New Zealand submitted the documents and data to the CLCS in April 2006. The CLCS began to examine New Zealand's submission in August 2008. It is expected that the recommendation for New Zealand will be approved by the CLCS at the forthcoming session, to be held in August and September 2008.
(2) The content of the submission
Executive Summary, Main Body and Supporting Data make up the documents required for the submission. Only the Executive Summary is posted in the public domain, i.e., the website of the CLCS, as shown below. The Executive Summary includes a description of the four areas of New Zealand's submission.
(3) New Zealand UNCLOS agencies
Close cooperation has been maintained under the framework of the Project, leading to a successful submission between scientists, diplomats, lawyers, and administrators. The Project has promoted their philosophy of New Zealand's submission through the making of presentations at relevant international conferences and the publication of a booklet. The online version of the booklet is available at the following URL:
(4) Provisions on the continental shelf beyond 200 nautical miles
Article 76 of UNCLOS on the extension of the continental shelf categorizes the sea bottom into the part belonging to the landmass and the part belonging to the deep ocean floor. Article 76 (4) stipulates the outer limits of the continental shelf. Article 76 (5) lays down the maximum lines of the extended continental shelf, i.e., such lines either shall not exceed 350 nautical miles from the territorial sea baselines or shall not exceed 100 nautical miles from the 2,500 metre isobath. It depends on the actual feature of the seabed which formula is applied. The outer limits line can be delineated by straight lines not exceeding 60 nautical miles in length.
Thus, the concept of the extension of the continental shelf is a simple one. Its application to actual sea beds is accompanied many difficulties, however. The case of New Zealand is shown below.
(5) UNCLOS surveys by New Zealand
According to the result of the analytical study, four areas (Northern, Eastern, Western and Southern areas) were identified as potential areas for the extension of the continental shelf. Detailed surveys, including multi-channel seismic reflection, magnetic and gravity field data collecting, and rock dredging, were carried out for 350 days in total. Multi-beam swath surveys were carried out at the three areas with complex features, i.e., Resolution Ridge, Bollons Seamount, and Wishbone Ridge. Not all of the results of these multi-beam swath surveys were successful for the purpose of the submission.
(6) Ambiguities in Article 76
In the process of preparing the documents for the submission, New Zealand faced the difficulty of the ambiguities in Article 76, such as how the prolongation of the land mass is applied, the difficulty of application of "evidence to the contrary, Ethe difficulty of application of "oceanic ridges, E"submarine ridges, Eand "submarine elevations, Ehow to select the exact 2,500 meter isobath in complex sea bottom features, and the computation of sediment thickness. These issues are shared by Japan, which also has complex sea bottom features around its landmass.
(7) Unique features of sea bottom around New Zealand
Why are sea bottoms around New Zealand so complex? Because New Zealand is astride an active plate boundary between the Australian and Pacific Plates. A few examples of the complex sea bottom are shown below.
The first example is the sea bottom from Three Kings Ridge to the South Fiji Basin in the northern area. There are several seamounts and several points that can be considered a "foot of slope. EConsideration of geophysics data and seismic reflection data brought the exact "foot of slope. E
The second example is the sea bottom from Chatham Rise through Hikurangi Plateau to the Southwest Pacific Basin in the eastern area. There are also several points that can be considered "foot of slope. EThe Project Team for the submission demonstrated that Hikurangi Plateau is a large igneous province as a whole and was accreted to New Zealand about 110-100 million years ago by geological data and tectonics setting data. It is proof that Hikurangi Plateau is connected to the landmass of New Zealand.
The New Zealand Team explained these things at the session of the CLCS for their consideration. It is expected that the recommendations for New Zealand will be made by the CLCS in the near future.
(8) Summary
The submission to the CLCS for extending the continental shelf is an investment in the future. After the recommendation made by the CLCS, Coastal States can delineate the outer limits of the continental shelf, which will confirm the sovereign rights, bring clarity and certainty to the investment, and make a significant contribution to the economic and social prosperity of the State.
Distributed Paper (2.2MB)
* This seminar was carried out as the OPRF project "Support for Delineation of the Outer Continental Shelf," under the patronage of The Nippon Foundation using proceeds from motorboat racing.

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