Halemaumau crater is a crater within the (inner) caldera. It contained a lake of lava between 1883 and 1924, when it exploded. The width of the crater was…
Inner caldera floor and Halemaumau crater.
Steam vents on the outer caldera. The inner caldera floor is a few dozen meters below.
Inner caldera.
Inner caldera.
Edge of Halemaumau crater.
Halemaumau crater.
Pahoehoe lava is composed chiefly of black basalt glass. Gases emitted by the flowing lava form many small bubbles, called vesicles.
Aa lava forms when sticky, viscous flows break up while moving downslope. The reddish brown color is caused by oxidation as the lava cools.
