Ontong Java Atoll in the context of Lord Howe Island

8°00′S 159°00′E / 8.000°S 159.000°E / -8.000; 159.000

The Solomon Islands is an island group (archipelago) in the western South Pacific Ocean, north-east of Australia. The archipelago is in the Melanesian subregion and bioregion of Oceania and forms the eastern boundary of the Solomon Sea. The many islands of the archipelago are distributed across the sovereign states of Papua New Guinea and Solomon Islands. The largest island in the archipelago is Bougainville Island, which is a part of the Autonomous Region of Bougainville (currently a part of Papua New Guinea) along with Buka Island, the Nukumanu Islands, and a number of smaller nearby islands. Much of the remainder falls within the territory of Solomon Islands and include the atolls of Ontong Java, Sikaiana, the raised coral atolls of Bellona and Rennell, and the volcanic islands of Choiseul, Guadalcanal, Makira, Malaita, New Georgia, the Nggelas, Santa Isabel, and the Shortlands. The Santa Cruz Islands are not a part of the archipelago.

6°14′40″S 155°23′02″E / 6.24444°S 155.38389°E / -6.24444; 155.38389

The North Solomon Islands form a geographical area covering the more northerly group of islands in the Solomon Islands archipelago and includes Bougainville and Buka Islands, Choiseul, Santa Isabel, the Shortland Islands and Ontong Java Atoll. In 1885 Germany declared a protectorate over these islands forming the German Solomon Islands Protectorate. With the exception of Bougainville and Buka, these were transferred to the British Solomon Islands Protectorate in 1900. Bougainville and Buka continued under German administration until the outset of World War I, when they were transferred to Australia, and after the war, were formally passed to Australian jurisdiction under a League of Nations mandate.

The Ontong Java Plateau (OJP) is a massive oceanic plateau located in the southwestern Pacific Ocean, north of the Solomon Islands.The OJP was formed around 116 million years ago (Ma), with a much smaller volcanic event around 90 Ma. Two other southwestern Pacific plateaus, Manihiki and Hikurangi, now separated from the OJP by Cretaceous oceanic basins, are of similar age and composition and probably formed as a single plateau and a contiguous large igneous province together with the OJP.When eruption of lava had finished, the Ontong Java–Manihiki–Hikurangi plateau covered 1% of Earth's surface and represented a volume of 80 million km (19 million cu mi) of basaltic magma.This "Ontong Java event", first proposed in 1991, represents the largest volcanic event of the past 200 million years, with a magma eruption rate estimated at up to 22 km (5.3 cu mi) per year over 3 million years, for a total several times larger than the Deccan Traps.The smooth surface of the OJP is punctuated by seamounts such as the Ontong Java Atoll, one of the largest atolls in the world.