100-Meter New Island Off Coast of Japan Made From Undersea Volcano Ioto Eruption Won't Last Long, Says Experts

Following its eruption, Japan's undersea volcano Ioto created a 100-meter-long new island, but experts predict this island won't endure for very long.

Ioto: Japan's Undersea Volcano

Three weeks ago, an underwater volcano off the coast of Japan erupted, giving a unique glimpse into the formation of a tiny new island, but experts warn that the presence of the new island might not last long.

The nameless underwater volcano, known as Ioto in Japan, is situated around half a mile off the southern coast of Iwo Jima. On October 21, the volcano began erupting again.

Rocks and volcanic ash piled up on the shallow seabed within ten days, with the tip rising above the water's surface. As of early November, Yuji Usui, an expert in the volcanic section of the Japan Meteorological Agency, estimates that it had grown into a new island with a circumference of around 328 feet and a maximum elevation of 66 feet above sea level.

A New Island is Formed But Won't Last

Recent volcanic activity near Iwo Jima has led to the formation of a new island, marking a noteworthy development, as stated by Usui. Although undersea eruptions in the area have been observed in recent years, the emergence of a new island is a significant occurrence. Despite an initial increase, volcanic activity has subsided, causing the newly formed island to shrink due to its "crumbly" composition easily eroded by waves, according to Usui.

Ongoing analysis by experts aims to understand the deposits, with the island's potential longevity hinging on its composition-lava or more durable materials could prolong its existence. Usui emphasizes that observation is now key, acknowledging the uncertainty of the island's lifespan.

Historical examples, like the Hunga Tonga eruptions, highlight the transient nature of such formations. Despite recorded eruptions in 1852, 1857, 1984, and 2006, resulting in new land masses, these islands ultimately vanished due to erosion from waves and currents. Usui draws parallels with other instances globally, such as the 2013 Nishinoshima eruption near Tokyo the emergence of islands following seismic events in Pakistan in the same year, and a Tongan submarine volcano eruption in 2015.

Japan, home to 111 of the world's 1,500 active volcanoes, faces such occurrences frequently, given its location on the Pacific "Ring of Fire," according to the Japan Meteorological Agency.

Volcanic Islands are Different

Volcanic islands, the peaks of underwater volcanic mountains, result from localized magma generation hot spots. As older volcanoes form shields and shift northwest due to ocean floor and crust movements, the percentage of sandy shores increases on these aged islands.

The Hawaiian Islands, being young, lack large rivers for sediment supply, resulting in smaller beaches. Unique calcareous sand, primarily composed of shells and test remnants from reef-dwelling organisms, characterizes these beaches.

Exceptions include basalt sand near stream mouths and black volcanic glass sand on some Hawaii beaches, formed by steam explosions from lava meeting the ocean.