Lava and the sea

Every time I have gone out into the field thus far, something awesome and new has happened. Well, at least awesome and new to me. On Thursday, at 12:15 pm the east rift zone lava flows finally hit the ocean (now over 600 meters from Sunday's flow margins). This is referred to as an "ocean entry" and is a spectacular, but dangerous phenomenon.

When the hot pahoehoe lava meets the sea, a plume of white steam erupts. In the picture above you can barely see the glistening lava behind the thick steam. The steam is comprised of lingering dissolved gas molecules in the lava that flashes to steam upon contact with the cold water, as well as vaporized H2O and a high concentration of vaporized salt from the ocean water.

Be careful not to stray too close to the steam clouds though, because unlike the refreshing feel of a spa steam room, this steam could be speckled with pieces of glass, quickly cooled and solidified lava, ejected from flow. Moreover, if you are close enough to be consumed by the steam plume, it means you are also within spraying distance of very, very hot water. Heated by the hot lava, sea water within a few meters of the flow entry point can have temperatures up to 69 degrees Celsius.

As more and more lava gushes into the ocean a miraculous thing happens: new land is created. But this fledgling island rock is highly unstable. Intermittently large slabs of newly erected land will collapse, or calve, into the ocean. This is yet another in a long laundry list of reasons why you should not get too close to flows entering the ocean. Plus, this huge collapse can send soccer ball size pieces of rock up to 120 meters (or slightly farther than a football field)!

(Both pictures were taken by me, Zahra Hirji, on behalf of USGS.)