Figures

1.  International Bathymetric Chart of the Arctic Ocean from:

http://www.ngdc.noaa.gov/mgg/bathymetry/arctic/arctic.html

The area outlined in red represents the region shown in Figs. 2, 4 and 5.

2.  Map of Amerasia Basin of the Arctic Ocean adjacent to Alaska, showing physiographic features including Northwind Ridge and Northwind Basin. Bathymetry contours generated with Generic Mapping Tools using the ETOPO2 world-wide gridded 2-minute database:

http://www.ngdc.noaa.gov/mgg/fliers/01mgg04.html

3.  U.S. Coast Guard Cutter Polar Star (WAGB-10) in sea ice, Arctic Ocean.

4.  Tracklines of seismic reflection profiles acquired over the Canada Basin, Northwind Ridge, and Northwind Basin during late summer of 1988, 1992 and1993. On the full size image, the reflection profile number and an image of the data can be displayed by clicking on any reflection line on the map.

5.  Tracklines of sonobuoy refraction profiles acquired over the Canada Basin, Northwind Ridge, and Northwind Basin during late summer of 1988, 1992 and1993. On the full size image, the sonobuoy profile number and an image of the data can be displayed by clicking on any refraction line on the map.

6.  Schematic of the single-air gun seismic system used in 1988. Towing point was the "J"-frame on the stern of the Polar Star.

7.  Schematic of the seismic system used in 1992 and 1993. Towing point was the stern chock of the Polar Star. Total volume of the air gun arrays used in 1992 and 1993 ranged from 674 to 1303 cubic inches.

8.  Schematic of the tow package umbilical first used in 1992.

9.  Photographs of the seismic system used in 1992 and 1993 on deck, showing the air guns and air-gun frame, the towing weight, and the conical steel "trumpet" that protected the wet end connection of the compressed air hoses, air-gun trigger lines, and electrical conductors for the hydrophone streamer and depth transducers.

10.  Shot point map of cruises conducted in 1988, 1992 and 1993. The map is broken up into three files (.pdf) for better viewing.