This article may be of interest to you:
On November 17 and 18, 2008 nine H-Bombs were exploded below the Arctic Ocean, near the North Magnetic Pole, within Canadian waters. The explosions were concentrated in an area about 16 km by 16 km (10 miles by 10 miles), were in the 5 to 10 Megaton range, all were 10 km (6.2 miles) deep.
http://www.wariscrime.com/2008/11/21...-arctic-ocean/