Contours of Hawaiian Volcanoes – February 12th, 2009
This radar (ASAR) image gives a sharp view of the contours of the Mauna Loa (bottom) and Mauna Kea (top) volcanoes, Hawaii. The white dots along the coastline and loosely scattered among the hills are towns.
Mauna Loa is shaped like a shield because its lava is extremely fluid (it has low viscosity). Its slopes are not steep.
Mauna Kea, on the other hand, is in the post-shield stage of volcanic evolution. About 200,000 to 250,000 years ago, its appearance was probably quite similar to that of its neighbor Mauna Loa today, a smooth shield volcano with a large summit caldera.
Following the transition, eruptions became more explosive in character, resulting in the formation of numerous overlapping cinder cones which eventually filled and completely obscured the caldera. These cinder cones now form the peaks at the summit of Mauna Kea, with several of them exceeding 13,500 feet (4,100 m) in elevation.