South Sandwich Is
Protector Shoal seamount, located 56 km NW of Zavodovski Island, forms the northernmost volcano of the arcuate South Sandwich Islands. The broad, gently sloping cone rises from a depth of 1200 meters to within 27 meters of the sea surface. The submarine volcano has a gentle gradient to the north, but is steeper on the south side. At least two satellitic cones are present. Large amounts of rhyolitic pumice, first detected by the Royal Navy Ice Patrol Vessel , were ejected during its only recorded eruption in 1962 and formed an extensive pumice raft which drifted as far as New Zealand.