National Geographic : 2011 Apr
With temperatures around 1800°F, the lava lake is wildly erratic. As molten rock meets the air, it cools and forms plates on the lake's surface (top left). Rising gas bubbles often explode and can splatter lava some 60 feet in the air (bottom left), sending waves of lava lapping over the rim (above). Scientists aren't sure of the lake's depth, though recent lava samples indicate the magma originated in the Earth's mantle more than 46 miles below.