Halema'uma'u crater is the smaller depression (about 1/2 mile in diameter) within the larger Kilauea Caldera which is about 2 by 3 miles wide.
This shot of Halema'uma'u crater was taken from the Thomas Jaggar Museum (named after the volcanologist who started the lab here and headed it for many years.) More on Jaggar at: http://hvo.wr.usgs.gov/volcanowatch/1997/97_03_21.html
While the weather kept changing on us, some of this haze is caused by sulphur gasses from the volcano itself.
First visited by a Westerner (missionary and author William Ellis) in 1823, the caldera was then almost 1000 feet deep and filled with raging lakes of molten lava. In the 19th century, the floor collapsed 4 times. This pretty much stopped for the Caldera by 1905. However Halemaumau Crater has had 7 new lava flows since then.
This picture of Pele, the Hawaiian goddess of fire, hangs at the Jaggar Museum. Pele lives in the Halema'uma'u crater. We didn't see her while she was there as she was having a bad hair day. This happens a lot when your tresses are lava.
The name of the crater: Halema'uma'u means "house of ferns." Ferns love the humidty around the steam vents.
The museum displays a'a lava -- caused when the lava breaks up while flowing downhill. The reddish-brown color is caused by oxidation as the flow cools.
The Thomas Jaggar Volcano Museum shows this early siesmograph -- it makes its mark on a messy (and hard-to-store) carbon drum
More modern equipment monitors various sites on the Big Island...
Including this web cam (URL unknown)
Here's an interesting fissure on the Caldera floor.
