There are 10 identified volcanoes along the 300 km long ridge from Bridgeman Island to Deception Island. Deception (30 km diameter base), Penguin (8 km diameter base), and Bridgeman (25 km diameter base) islands are the tops of Pleistocene-Recent stratovolcanoes, while 7 additional submarine volcanoes exist as seamounts, with the Orca Seamount being the largest (20 km diameter base).