Topography, volume of lava factors in Hawaii explosion
HONOLULU (AP) - The U.S. Geological Survey says explosions of varying sizes happen whenever 2,000-degree Fahrenheit lava enters much colder seawater.
But the large explosion that blasted lava onto a tour boat Monday could also have to something to do with the offshore topography and the amount of molten rock currently entering the ocean in that area.
USGS Geologist Janet Babb says that lava mixing with water is always explosive, but there are also times that molten rock can become encrusted underwater, and when that crust breaks the interaction it can cause huge steam explosions that can hurl debris hundreds of yards (meters) into the air.
The volume of lava now entering the sea is much higher than in previous flows, Babb says, and because the ocean is relatively shallow in that area, the lava has more opportunity to build up and explode near the surface.