Ephemeral islands

Calais ( , , traditionally , ) is a French major port city in the Pas-de-Calais department, of which it is a subprefecture. Calais is the largest city in Pas-de-Calais. The population of the city proper is 67,585; that of the urban area is 144,488 (2022). Calais overlooks the Strait of Dover, the narrowest point in the English Channel, which is only wide here, and is the closest French town to England. The White Cliffs of Dover can easily be seen from Calais on a clear day. Calais is a major port for ferries between France and England, The Channel Tunnel has connected Calais and Folkestone sin

volcano in Tonga

atoll in the Pitcairn Islands, British Overseas Territories

submerged volcanic island south of Sicily

isolated and uninhabited Japanese island in the Pacific Ocean considered part of the Volcano Islands and administered as part of Tokyo's Ogasawara subdistrict

former island in Pakistan

is a submarine volcano located about 450 kilometers south of Tokyo on the Izu-Ogasawara Ridge in the Izu Islands. Volcanic activity has been detected there since 1869. Since then it has undergone more eruptions, the most powerful of which resulted in the appearance and disappearance of a small island.

Kolumbo () is an active submarine volcano in the Aegean Sea in Greece, about northeast of Cape Kolumbo, Santorini (Thira) island. The largest of a line of about twenty submarine volcanic cones extending to the northeast from Santorini, it is about in diameter with a crater across. It was first noticed by humans when it breached the sea surface in 1649–1650. The Smithsonian Institution's Global Volcanism Program treats it as part of the Santorini volcano, though at least one source maintains that it is a separate magmatic system.

Jólnir () was formerly a volcanic island south of Iceland. It was a former vent of Surtsey, along with Syrtlingur and Surtla. It emerged from the ocean as a result of active plate tectonics between December 1965 and July 1966. Oceanic erosion cyclically wore down the new lava as it formed, and the island sank below the surface several times.

Kavachi is one of the most active submarine volcanoes in the south-west Pacific Ocean. Located south of Vangunu Island in the Solomon Islands, it is named after a sea god of the New Georgia Group islanders and is also referred to locally as Rejo te Kavachi ("Kavachi's oven"). The volcano has become emergent and then been eroded back into the sea at least eight times since its first recorded eruption in 1939.

Kuwae was a landmass that existed in the vicinity of Tongoa and was destroyed by volcanic eruption in fifteenth century, probably through caldera subsidence. The exact location of the caldera is debated. A submarine caldera, now known as Kuwae caldera and which is located between the Epi and Tongoa islands, is a candidate. Kuwae caldera cuts through the flank of the Tavani Ruru volcano on Epi and the northwestern end of Tongoa. Another potential candidate is a proposed caldera between Tongoa and Tongariki.

mountain

volcanic island

is a submarine volcano that is part of the Volcano Islands in the Bonin Islands of Japan. It is located northeast of the island of South Iwo Jima.

island in Tonga

large submarine volcano in the north Atlantic between São Miguel and Terceira in the Azores

Island in Portugal

iceberg

mountain in Vietnam

island in Pakistan