Ch. 1— Summary, Issues, and Options * 7 



Box 1-B — A Source of Confusion: Geologic Continental Sheli; Jurisdictional Continental Shelf; 



Exclusive Economic Zone 



International and domestic law has established sev- 

 eral ocean zones to accommodate the exploration 

 and development of ocean resources. For instance, 

 "Outer Continental Shelf is used in the Outer Con- 

 tinental Shelf Lands Act to define the Federal off- 

 shore area in which mineral leasing is authorized. 

 The legal entity "Outer Continental Shelf is easily 

 confused with the "continental shelf," which is a 

 geologic subsea landform with scientific definition. 

 Establishment of the Exclusive Economic Zone (EEZ) 

 contributed more to the confusion. The EEZ over- 

 lays both the jursidictional Outer Continental Shelf 

 and the geological continental shelf (figure 1-1). 

 These overlapping zones seldom coincide exactly, 

 and in some instances the geologic continental shelf 

 may extend well beyond the 200-mile EEZ, while in 

 other cases where the shelf is narrow it may extend 

 only a few miles seaward, well short of the line of 

 demarcation for the EEZ. 



The Outer Continental Shelf Lands Act of 1953 

 defines Outer Continental Shelf as "all submerged 

 lands lying seaward and outside of the area of lands 

 beneath navigable waters . . . [three-mile State- 

 controlled territorial sea] . . . , and of which the sub- 

 soil and seabed appertain to the United States ..." 

 A more precise definition of the continental shelf 

 emerged from the internationed Convention on the 

 Continental Shelf in 1958, which described it as ex- 

 tending from shore to a depth of 200 meters or be- 

 yond that limit to where the depth of the superjacent 

 water admits of exploitation of the natural resources. 



The 1958 international defimition of continental 

 shelf, therefore, is somewhat open-ended regarding 

 the seaward extension of the shelf and bases the de- 

 termination of the final outer boundary on techno- 

 logical capability to explore and exploit. The World 

 Court has limited the extent of the continental shelf, 

 at least in cases of boundary disputes, based on the 

 notions of proximity and natural prolongation. Be- 

 cause the land is the legal source of a state's marine 

 jurisdiction, it must be established that the sub- 

 merged lands are in fact physical extensions of the 

 state's territory.* 



The United Nations Law of the Sea Conference, 

 which concluded in 1982, established yet another in- 

 ternational definition for the continental shelf. Arti- 

 cle 76 of the Law of the Sea Convention (LOSC) de- 

 fines it as the "sea-bed and subsoil of the submarine 



areas that extend beyond its territorial sea through- 

 out the natural prolongation of its land territory to 

 the outer edge of the continental margin ..." Where 

 the "continental margin" extends beyond the bound- 

 ary of the 200-mile EEZ, LOSC requires that signa- 

 tory nations establish a finite outer limit based on 

 formulae for determining where the foot of the con- 

 tinental slope meets the abyssal depths of the ocean. 

 However, regardless of where such an outer point 

 may lie as determined by formulae, the continental 

 shelf can neither extend more than 350 nautical mUes 

 from the coast, nor exceed 100 nautical mUes beyond 

 the 8,200 foot isobath (point of equal water depth). 



Since the United States is not signatory to the re- 

 cent LOSC, the limitations imposed by Article 76 

 do not apply. Some legal analysts believe that the 

 1958 Convention on the Continental Shelf with its 

 open-ended, technology-determined definition of the 

 outer boundary of the shelf would apply unless Con- 

 gress redefines its boundaries in subsequent EEZ im- 

 plementing legislation. Under the more liberal 1958 

 interpretation, the Outer Continental Shelf could per- 

 haps extend several hundred miles beyond the EEZ. 

 According to this legal reasoning, with disagreement 

 among legal analysts on the overlapping effects of the 

 EEZ, the Outer Continental Shelf, the continental 

 shelf within the meaning of the 1958 Convention on 

 the Contintental Shelf, cmd international ocean space 

 beyond, there is the possibility that a legal ' 'no-man's 

 Ijuid" exists offshore where no domestic law governs. 



The geological definition of the continental shelf 

 is only slightly more precise than the several legal 

 definitions. The Dolphin Dictionary of Geological 

 Terms defines it as the "gently sloping, shallowly 

 submerged marginal zone of the continents extend- 

 ing from the shore to an abrupt increase in bottom 

 inclination; greatest average depth less than 600 feet, 

 slope generally less than 1 to 1,000, local relief less 

 than 60 feet, width ranging from very narrow to more 

 than 200 miles." For scientific purposes, the defini- 

 tion is adequate since geologists can generally agree 

 on where the continental shelf begins and ends. The 

 industry seeking to explore and develop resources of 

 the seabed and government administrators charged 

 with managing the outer continental shelf have more 

 difficulty in deciding the jurisdictional limits of the 

 Outer Continental Shelf. 



•NoTtfa Sea Continental Shelf, 1969, I.C.J. 3. 



