Gallery: Lava Features
A'a
A'a has a hot, molten interior, with a thinner layer of solid clinker on top which gets carried along. The clinker falls off and becomes buried beneath the flow.
UHH Geology professor Jim Anderson provides scale for an a'a flow.
The distinct layers of an a'a flow are: clinker on top, moten interior, clinker buried underneath.
Pahoehoe
Pahoehoe lava has a smoother surface than a'a.
Although this pahoehoe has formed a hard crust, the lava continues to flow.
An individual lobe of molten pahoehoe that breaks out is called a toe.
Gino Valeriani samples pahoehoe.
Lava can still flow beneath thick crust.
Pahoehoe lava often forms a ropy skin.
A sample of molten lava quickly cools.
Skylights
A lava tube starts out as a flow, but the sides of the flow cool and harden, resulting in a tube-shaped insulating layer that allows for efficient flow of the remaining lava within. When a portion of the insulating layer breaks open, it is called a skylight, and the molten lava can be seen flowing beneath. Never stand over a lava tube!
As this "river" of lava continues to flow, eventually the sides and top will harden into crust, and a lava tube may develop.
Here, a skylight has formed over a lava tube. At night, the lines of the lava flow are distinct.
Lava can be seen flowing in a skylight.
Rocks in the tube are heated by lava.
Lava enters the ocean
The Big Island is getting bigger every day. Lava entering the ocean is often explosive, so it's best to view it from a safe distance, far away.
Lava enters the sea in Hawaii Volcanoes National Park.
A toe of pahoehoe is about to be quenched by an ocean wave.
Black sand is created as lava enters the sea.
Occasionally, after a bench collapse, a "firehose" of lava will pour into the ocean, as the tube is suddenly exposed.
Sometimes seawater enters the lava tube and mixes with hot lava, creating spectacular pseudo-fountaining.