Mauna Kea, is a dormant volcano on the island of Hawaii. Standing 4,207 m above sea level, its peak is the highest point in the state of Hawaii, much of the mountain is under water, when measured from its oceanic base, Mauna Kea is over 10,000 m tall. Mauna Kea is about a years old, and has thus passed the most active shield stage of life hundreds of thousands of years ago. In its current post-shield state, its lava is more viscous, Mauna Kea last erupted 6,000 to 4,000 years ago and is now considered dormant. In Hawaiian mythology, the peaks of the island of Hawaiʻi are sacred, an ancient law allowed only high-ranking aliʻi to visit its peak. Ancient Hawaiians living on the slopes of Mauna Kea relied on its extensive forests for food, when Europeans arrived in the late 18th century, settlers introduced cattle, sheep and game animals, many of which became feral and began to damage the mountains ecological balance. With its high elevation, dry environment, and stable airflow, since the creation of an access road in 1964, thirteen telescopes funded by eleven countries have been constructed at the summit. The Mauna Kea Observatories are used for research across the electromagnetic spectrum from visible light to radio. Their construction on a landscape considered sacred by Native Hawaiians continues to be a topic of debate, Mauna Kea is one of five hotspot volcanoes that form the island of Hawaii, the largest and youngest island of the Hawaiian–Emperor seamount chain. Of these five volcanoes, Mauna Kea is the fourth oldest and 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, 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, Mauna Kea is over 3,200 km3 in volume, so massive that it and its neighbor, Mauna Loa, depress the ocean crust beneath it by 6 km. The volcano continues to slip and flatten under its own weight at a rate of less than 0.2 mm per year, much of its mass lies east of its present summit. Mauna Kea stands 4,205 m above sea level, just 35 m higher than its neighbor Mauna Loa, measured from its base on the ocean floor, it rises over 10,000 m, significantly greater than the elevation of Mount Everest above sea level. Like all Hawaiian volcanoes, Mauna Kea has been created as the Pacific tectonic plate has moved over the Hawaiian hotspot in the Earths underlying mantle. The Hawaii island volcanoes are the most recent evidence of this process that, the prevailing, though not completely settled, view is that the hotspot has been largely stationary within the planets mantle for much, if not all of the Cenozoic Era. However, while Hawaiian volcanism is well-understood and extensively studied, there remains no definite explanation of the mechanism causes the hotspot effect. Lava flows from Mauna Kea overlapped in complex layers with those of its neighbors during its growth, most prominently, Mauna Kea is built upon older flows from Kohala to the northwest, and intersects the base of Mauna Loa to the south
Image: Mauna Kea from the ocean
A stone structure or ahu facing Mauna Kea, on Saddle Road between Mauna Kea and Mauna Loa.