How long before Loihi breaks the surface? And what will happen when it does?

rocky Ryan

Hi again Ryan,

I don't think anyone really knows when Lo'ihi will break the surface. The answer I've heard most often is about 10,000 years, but I don't think anyone would want to wager their life (or even a few $$) on that number. It still has almost 1 km to go so you and I will certainly not be around to see it.

As for what will happen, it will be quite exciting. Because of the water pressure, Lo'ihi eruptions now days are very quiet (the water pressure prevents steam from forming when hot lava is erupted). However, when the summit gets closer and closer to the surface, the water pressure will (of course) get lower and lower. Soon, steam explosions will be able to occur and the result will what are called "hydro-magmatic" explosions. These are very violent, and result from the contact between erupting lava and shallow water. These eruptions produce ash rather than lava (because the explosions break everything into small pieces), and for this reason the new island will be very prone to being washed away by the waves. If the eruptions continue long enough though, a ring of ash will eventually isolate the erupting vents from the ocean water and as soon as that happens regular lava fountains will occur, producing lava flows. These lava flows are much more resistant to erosion and as soon as they come along the island is more-or-less permanent.

These processes were all well-observed during the formation of Surtsey off the southern coast of Iceland in 1963.

sincerely,

Scott Rowland, University of Hawaii

For an example of submarine volcanism breaking the surface look at our pictures of the recently erupting Metis Shoal in the current volcanoes section of VolcanoWorld. 

Other Categories        Other Questions

To VolcanoWorld