Fukutoku-Okanoba Volcano

Fukutoku-Okanoba Volcano Latest News

Japan’s Coast Guard recently reported signs of activity at the Fukutoku-Okanoba submarine volcano. 

About Fukutoku-Okanoba Volcano

• It is an active submarine volcano that is part of the Volcano Islands of Japan in the Pacific Ocean.  
• It is part of the Izu-Bonin arc formed by subduction of the Pacific Plate beneath the Philippine Sea Plate. 
• Its summit is just 14 meters (46 feet) below sea level, allowing Surtseyan eruptions to breach the surface.  
• Composition is tholeiitic basalt, typical of arc front volcanism. 
• It remains active with intermittent submarine eruptions and discoloured water since 2013. 
• Eruptions are explosive with pumice rafts, discoloured water, and occasional ephemeral island formation. 
• The 2021 eruption produced massive pumice rafts that drifted thousands of kilometres across the Pacific, impacting shipping and beaches. 
• The volcano’s frequent activity and shallow depth make it one of the most dynamic submarines, with eruptions often detected by satellite discoloration.  

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What is a Surtseyan Eruption?

• It is a type of volcanic eruption that takes place in shallow seas or lakes. 
• It is named after the island of Surtsey off the southern coast of Iceland. 
• When magma rises close to the surface of the water, it can come into contact with the water and cause it to flash to steam. 
• The sudden increase in volume of the steam can cause an explosion, which can fragment the magma into small pieces. 
• These pieces of magma, called tephra, can be ejected into the air, forming an ash column. 
• These eruptions are commonly phreatomagmatic eruptions, representing violent explosions caused by rising basaltic or andesitic magma coming into contact with abundant, shallow groundwater or surface water. 
• Tuff rings, pyroclastic cones of primarily ash, are built by explosive disruption of rapidly cooled magma.
• Surtseyan eruptions are relatively common, and they can be found all over the world.  
• Surtseyan eruptions can be very dangerous. 
  • The ash and rock fragments that are ejected into the air can travel long distances, and they can be a hazard to ships and aircraft. 
  • The sudden expansion of steam can also cause shock waves, which can damage buildings and other structures.

News: REUT