A close view of the 1984 eruption of Mauna Loa Volcano in Hawaii, taken from a light plane, shows both flowing and solidified lava. The red flow is molten pahoehoe lava from the eruption; the black flows are solidified lava from previous but recent eruptions only a few tens of years old; and the reddish-brown flows whose surface minerals containing iron have weathered to rust are prehistoric in age. For some idea of scale, the black lava flow which moved from right to left is about 100 meters across.                 
                                              Photo copyright R.W. Decker