mauna kea is one of five volcanoes that form the island of hawaii, the largest and youngest island of the hawaiian–emperor seamount chain. of these five hotspot volcanoes, mauna kea is the fourth oldest and fourth most active. it began as a preshield volcano driven by the hawaii hotspot around one million years ago, and became exceptionally active during its shield stage until 500,000 years ago. mauna kea entered its quieter post-shield stage 250,000 to 200,000 years ago, and is currently dormant. mauna kea does not have a visible summit caldera, but contains a number of small cinder and pumice cones near its summit. a former summit caldera may have been filled and buried by later summit eruption deposits.