THE 2,500 METRE ISOBATH (CHAPTER 4)

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THE 2,500 METRE ISOBATH (CHAPTER 4)
Harald Brekke
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The role of the 2,500 m isobath

• The fixed points comprising the line of the outer
  limits of the continental shelf on the sea-bed,
  drawn in accordance with paragraph 4 (a) (i ) and
  (ii), either shall not exceed 350 nautical miles
  from the baselines .. or shall not exceed 100
  nautical miles from the 2,500 metre isobath,
  which is a line connecting the depth of 2,500
  metres
  (Paragraph 5, article 76)

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Relevant bathymetric data
Primary data - Single-beam echo soundings -
Multi-beam echo soundings Complementary data -
Bathymetric side-scan sonar measurements -
Interferometric side-scan sonar measurements -
Seismic reflection-derived bathymetric
measurements (See 4.2.1 - 2)
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Ice-covered areas

• In special cases such as in ice-covered areas the
  CLCS may regard also the following as primary
  data
• Seismic reflection-derived bathymetric
  measurements
• Interferometric side-scan sonar measurements
  (See 4.2.3)

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Selection of points along 2,500 m isobath for
delineating the 100 M maximum limit

• The 2,500 m isobath may occur as multiple
  repetitions along the continental margin
• Use the first 2,500 m isobath from the baselines
  that conforms to the general configuration of the
  continental margin, unless there is evidence to
  the contrary (See 4.4.2)