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BC’s Tales of the Pacific | Kavachi, the disappearing volcano

BORN of massive earthly forces in the depths of the ocean and the guts of the planet, Pacific islands come from violent beginnings.

We can witness the birth of an island when an underwater volcano erupts to the surface, building a new landmass that will eventually host life.  Kavachi, an underwater volcano in the Solomon Islands, is such a place.  Actually, Kavachi has grown into an island many times.  It has a most unusual history.

Named after the sea god of New Georgia, Kavachi has emerged from the surface, then collapsed back below at least eight times since 1939.  It is the peak of a massive underwater mountain with a base five miles across at the sea floor.  In a typical instance the volcano erupts to spill molten lava and hot gases into the sea.  If the lava piles up fast enough it eventually breaks the surface, resulting in gas clouds and explosive debris.  During a 2003 eruption an island formed that rose almost fifty feet above sea level, but it sank once again due to wave action and a settling of the cooled lava rock. 

It is fascinating how quickly life moves into a volcano like Kavachi.  When eruptions occur the area is a zone of death, with water rising above the boiling point, toxic gases bubbling forth and deadly mineral clouds adrift in the currents.  Yet within hours, while minor eruptions still burst forth, fish come exploring.  During a recent eruption near the big island of Hawaii, scientists sent a robotic underwater vehicle to study the lava flows.  Sharks and rays glided past the camera, untroubled by the danger they were in.  The potential for food or a new living space outweighed the risks of getting boiled.  Perhaps they were just as curious as we are about these events. 

For amazing video footage that will inspire and educate, look up Kavachi volcano and underwater volcanic eruptions on  You will get a fish-eye view of island building.  Lava spews forth into the chilly sea water, quickly cooling to form new, unstable rock formations.  If the buildup is too steep or lopsided it will eventually lead to an underwater avalanche, something no scuba diver wants to be near. 

If the new island stays above sea level two other processes begin.  First, life will inhabit the landmass.  Scientists study not only which life forms live there but how long it takes for them to gain a foothold.  Ferns and birds are the first to call the new island home, followed by trees and grasses.  Lizards and mammals always come last since they have the hardest time crossing bodies of water.  We are so familiar with this process that we are able to judge the age of an island based on the plants and animals found on it.

The second process is political.  The new island will be claimed by one existing country or another.  In the case of Kavachi, it is clearly within the territorial boundary of the Solomon Islands.  New Hawaiian islands occasionally pop up, as do fresh ones in the Bonins of Japan.  But sometimes it is not clear who can claim the new island and political haggling can occur.  Wars have nearly started over such things.  Considering that a country can claim the waters around an island up to two hundred miles in some cases, it is clear why even a speck of land such as Kavachi could have great political implications.  Fishing and mineral rights alone could be worth millions of dollars for a cash-starved island nation.

No one is likely to go to war over Kavachi.  It’s political future is secure.  So we can enjoy watching the earth do what it does and marvel at the way life always triumphs.

BC Cook, PhD lived on Saipan and has taught history for 20 years. He travels the Pacific but currently resides on the mainland U.S.