Mauna Kea on the island of Hawaii is a dormant post-shield volcano topped with cinder cones. It is approximately one million years old and last erupted about 4,600 years ago.
Mauna Kea's status as a post-shield volcano is evidenced by its low eruption rates, its lack of a caldera at the summit, the long fissure vents radiating from its summit, its steep and irregular topography and the chemical composition of its lava. These traits are in contrast to neighboring volcanoes Mauna Loa and Kilauea, both of which are still active. Shield volcanoes are so-named because their mountains take the shape of shields due to lava outflow.