A. Introduction

Owned by Harald Sund (Unlicensed)
Last updated: Oct 16, 2015 by Tore Sannes (Unlicensed)
4 min read

About this Tutorial Collection

According to Article 76, coastal states can - under certain geological conditions - extend their juridical Continental Shelf and thus gain marine sovereignty rights beyond the 200-nautical-mile limit of the Exclusive Economic Zone (EEZ). Submissions for an extended Continental Shelf need to be filed directly with the Commission on the Limits of the Continental Shelf (CLCS) and must contain detailed marine geo-scientific data describing e. g. the shape of the continental margin, the location of the foot of the continental slope and the sediment thickness. 

This tutorial collection will guide you through the process of analyzing different marine geo-scientific data and producing the documentation needed for an extended continental shelf submission. The order of the tutorials is more or less describing the suggested order in which a real submission would be done using the UNCLOS article 76 functionality in Geocap. 


In this set of tutorials you will learn how to:

  • Use Geocap in general
  • Create a new project
  • Import data
  • Calculated different distance lines and constraint lines.
  • Do analysis and set foot of slope points
  • Calculate Hedberg points 
  • Interpret seismic data
  • Depth convert interpretations and calculate sediment thickness 
  • Calculate Gardiner points
  • Generate a final outer limit line
  • +++

The Atlantis Project

The Atlantis project will be used as an example project in this tutorial, but you should also be able to follow the tutorial using your own data.The Kingdom of Atlantis is an imaginary state which has started to work on their extended continental shelf submission. Using this tutorial collection we are going to finalize the analysis and complete the Atlantis project using the functionality in Geocap Shelf.


The continental shelf of Atlantis

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UNCLOS Article 76


Below you will find the full definition of the continental shelf as stated in UNCLOS Article 76.

Definition of the continental shelf

  1. The continental shelf of a coastal State comprises the seabed and subsoil of the submarine areas that extend beyond its territorial sea throughout the natural prolongation of its land territory to the outer edge of the continental margin, or to a distance of 200 nautical miles from the baselines from which the breadth of the territorial sea is measured where the outer edge of the continental margin does not extend up to that distance.
     
  2. The continental shelf of a coastal State shall not extend beyond the limits provided for in paragraphs 4 to 6.
     
  3. The continental margin comprises the submerged prolongation of the land mass of the coastal State, and consists of the seabed and subsoil of the shelf, the slope and the rise. It does not include the deep ocean floor with its oceanic ridges or the subsoil thereof.
     
  4. (a) For the purposes of this Convention, the coastal State shall establish the outer edge of the continental margin wherever the margin extends beyond 200 nautical miles from the baselines from which the breadth of the territorial sea is measured, by either:
      1. a line delineated in accordance with paragraph 7 by reference to the outermost fixed points at each of which the thickness of sedimentary rocks is at least 1 per cent of the shortest distance from such point to the foot of the continental slope; or
      2. a line delineated in accordance with paragraph 7 by reference to fixed points not more than 60 nautical miles from the foot of the continental slope.
      (b) In the absence of evidence to the contrary, the foot of the continental slope shall be determined as the point of maximum change in the gradient at its base. 
       
  5. The fixed points comprising the line of the outer limits of the continental shelf on the seabed, drawn in accordance with paragraph 4 (a)(i) and (ii), either shall not exceed 350 nautical miles from the baselines from which the breadth of the territorial sea is measured or shall not exceed 100 nautical miles from the 2,500 metre isobath, which is a line connecting the depth of 2,500 metres.
     
  6. Notwithstanding the provisions of paragraph 5, on submarine ridges, the outer limit of the continental shelf shall not exceed 350 nautical miles from the baselines from which the breadth of the territorial sea is measured. This paragraph does not apply to submarine elevations that are natural components of the continental margin, such as its plateaux, rises, caps, banks and spurs.
     
  7. The coastal State shall delineate the outer limits of its continental shelf, where that shelf extends beyond 200 nautical miles from the baselines from which the breadth of the territorial sea is measured, by straight lines not exceeding 60 nautical miles in length, connecting fixed points, defined by coordinates of latitude and longitude.
     
  8. Information on the limits of the continental shelf beyond 200 nautical miles from the baselines from which the breadth of the territorial sea is measured shall be submitted by the coastal State to the Commission on the Limits of the Continental Shelf set up under Annex II on the basis of equitable geographical representation. The Commission shall make recommendations to coastal States on matters related to the establishment of the outer limits of their continental shelf. The limits of the shelf established by a coastal State on the basis of these recommendations shall be final and binding.
     
  9. The provisions of this article are without prejudice to the question of delimitation of the continental shelf between States with opposite or adjacent coasts.
     
  10. The coastal State shall deposit with the Secretary-General of the United Nations charts and relevant information, including geodetic data, permanently describing the outer limits of its continental shelf. The Secretary-General shall give due publicity thereto.