Mauna Kea, Hawaii's highest volcano, is seen here from the south at the broad Humuulu Saddle between Mauna Kea and Mauna Loa. The fresh lava flow in the foreground was emplaced during an 1843 eruption that originated on the NE rift zone of Mauna Loa. The flow traveled directly north to the Mauna Kea saddle, where it was deflected to the west. The irregular profile of the unvegetated summit region of Mauna Kea shield volcano is produced by a cap of cinder cones and pyroclastic ejecta that is not present at Mauna Loa.
Hawaii's two largest shield volcanoes, Mauna Loa (in the background to the south) and Mauna Kea, have dramatically differing profiles. Mauna Loa, the world's largest active volcano, has the classic low-angle profile of a shield volcano constructed by repetitive eruptions of thin, overlapping lava flows. Mauna Kea is also a shield volcano formed in the same manner, but its profile has been modified by late-stage explosive eruptions, which constructed a series of cinder cones that cap its summit.
Mauna Kea (left) and Mauna Loa (right), both over 4000 m above sea level, are the world's largest active volcanoes, rising nearly 9 km above the sea floor around the island of Hawaii. This aerial view from the NW shows the contrasting morphologies of these two shield volcanoes. In contrast to the smooth profile of Mauna Loa, Mauna Kea's early shield volcano morphology is modified by the late-stage products of explosive eruptions.