This document discusses mapping efforts in Alaska to support the United States' claims under the UN Law of the Sea Treaty. Specifically, it summarizes research from the HEALY 07-03 mission which mapped over 2,000 nautical miles of the seafloor in the Arctic. This data provided new insights into the shape of the continental margin and led to the discovery of a previously uncharted seamount, helping define the limits of the US extended continental shelf under the treaty.

1. Mapping in Support of Law ofMapping in Support of Law of
the Seathe Sea
Center for Coastal and Ocean Mapping / NOAA-UNH
Joint Hydrographic Center University of New
Hampshire, USA
A presentation onA presentation on
HEALY 07-03HEALY 07-03
to the Alaska Eskimo Whalingto the Alaska Eskimo Whaling
CommissionCommission
Larry Mayer and Andy Armstrong

2. UN Law of the Sea TreatyUN Law of the Sea Treaty
• A coastal nation may claim sovereignty over theA coastal nation may claim sovereignty over the
seabed and subsoil (including environmental protection)seabed and subsoil (including environmental protection)
of the continental margin beyond their current 200of the continental margin beyond their current 200
n.m. Exclusive Economic Zone (EEZ) under Article 76n.m. Exclusive Economic Zone (EEZ) under Article 76
of the United Nations Convention on the Law of theof the United Nations Convention on the Law of the
Sea (UNCLOSSea (UNCLOS))
• if… the shape of the seafloor meets certain criteriaif… the shape of the seafloor meets certain criteria
• thethe 2500 m (~8250 ft) depth line (contour)2500 m (~8250 ft) depth line (contour)
• the “foot of the slope” – (~13,000 – 16,000 ft)the “foot of the slope” – (~13,000 – 16,000 ft)

3. http://www.ccom.unh.edu

5. U.S. Law of the Sea MappingU.S. Law of the Sea Mapping

6. Leadline Single Beam Echo Sounder Multibeam Echo Sounder
Measuring the shape of the seafloorMeasuring the shape of the seafloor

10. A new perspectiveA new perspective  new insightsnew insights

11. Beringian MarginBeringian Margin

12. Beringian MarginBeringian Margin

13. Gulf of AlaskaGulf of Alaska

14. Gulf of AlaskaGulf of Alaska

15. Chukchi CapChukchi Cap

16. USCG HEALYUSCG HEALY

17. HEALY 03-02HEALY 03-02
~2000 n.m of~2000 n.m of
multibeammultibeam
echosounderechosounder
bathymetrybathymetry
8/10 ice8/10 ice

18. HEALY 2004HEALY 2004
~4000 nm~4000 nm ofof
multibeammultibeam
echosounderechosounder
10/10 ice10/10 ice

19. Redefinition of the 2500 m contour

20. Discovery and Mapping of aDiscovery and Mapping of a
Major SeamountMajor Seamount
Healy SeamountHealy Seamount

21. HEALY 07-03HEALY 07-03
Depart Barrow:Depart Barrow:
17 Aug. 0717 Aug. 07
Return BarrowReturn Barrow
15 Sept. 0715 Sept. 07
Additional science:Additional science:
1- current studies1- current studies
2- deployment of ice2- deployment of ice
monitoring buoysmonitoring buoys
3- knowledge of3- knowledge of
seafloor shapeseafloor shape
critical for climatecritical for climate
modelingmodeling