• Previous landmasses created by the volcano in the area eroded away within months
  • Coast guard found pumice volcanic rocks floating in the ocean across 37 miles northwest 
  • Scientist have not yet determined what type of volcanic rocks formed the landmass

Last week, Japan’s archipelago of over 6,800 islands added a new member after an undersea volcanic eruption created a landmass.

According to Japan’s coast guard, the new island has a 1km diameter and initially, it assumed the shape of a broken horseshoe. However, recent images revealed two crescent-shaped landmasses resembling a bracket. The new island formed in the Pacific Ocean about 50km ( 31 miles) south of Minami Iwoto, the southernmost island of the Ogasawara group and 1,200km (745 miles) south of Tokyo.

The island emerged from the water following an eruption of the underwater volcano Fukutoku-Okanoba. The new landmass is just the top of the conical head of the volcano, reported Forbes. Fukutoku-Okanoba is an active volcano and has erupted several times in the past, with the last eruption observed in 2010.

But this new landmass could disappear in the future like its ancestors. Eruptions in 1904, 1914 and 1986 at the site also formed a new landmass, however, it eroded below sea level within a few months. This time the new landmass could have a similar fate if it is made of ash and other loose fragments. Scientists have not yet determined what the island is made of. Continued volcanic activity at the site could form a hard and durable shell, which could resist weathering from constant waves.

The coast guard discovered the island on Aug. 15 when they observed an eruption in the area from the air. They also found pumice, a low-density volcanic rock floating across a 60-km (37 miles) area in a northwest direction, reported the Mainichi Shimbun.

As Fukutoku-Okanoba is located near Minami Iwoto Island, any new landmass there recognized as a naturally formed island by international standards would be added to Japan’s territory. The probable new addition would unlikely affect Japan’s territorial waters or its exclusive economic zone, given it does not erode away.

In 2013, weeks of volcanic activity near Japan’s Nishinoshima island gave rise to a new landmass, reported the Guardian. The new island eventually merged with Nishinoshima for a while, making the island resemble famous comic character Charlie Brown’s pet dog, Snoopy.

The Pacific Ring of Fire is where several of the Earth's tectonic plates meet and is the location of many earthquakes
The Pacific Ring of Fire is where several of the Earth's tectonic plates meet and is the location of many earthquakes AFP / Sabrina BLANCHARD