Category:Volcanism by ocean Volcanism by ocean. Oceans portalVolcanoes portal Subcategories This category has the following 7 subcategories, out of 7 total. Volcanoes by sea or ocean (10 C)A Volcanism of the Arctic Ocean (1 C, 3 P) Volcanism of the Atlantic Ocean (7 C, 4 P)C Volcanism of the Caribbean (1 C, 1 P)I Volcanism of the Indian Ocean (2 C, 3 P)P Volcanism of the Pacific Ocean (5 C, 11 P)S Volcanism of the Southern Ocean (1 C)