Mauna Kea (/ˌmɔːnə ˈkeɪ.ən/ or /ˌmaʊnə ˈkeɪ.ə/; ) is a volcano on the island of Hawaii. Standing 13,803 ft (4,207 m) above sea level, its peak is the highest point in the U.S. state of Hawaii. However, much of the mountain is below sea level; when measured from its oceanic base, the total height difference is 33,500 ft (10,200 m), significantly taller than the elevation of Mount Everest (8,848 m/29,029 ft). Mauna Kea is about two million years old, and 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, resulting in a steeper profile. Late volcanism has also given it a much smoother appearance than its neighboring volcanoes: contributing factors include the construction of cinder cones, the decentralization of its rift zones, the glaciation on its peak, and the weathering effects of the prevailing trade winds. Mauna Kea last erupted 4,600 years ago. According to the USGS, as of January 2012, the Volcanic-Alert Level is "Normal".
In Hawaiian mythology, the peaks of the island of Hawaii are sacred, and Mauna Kea is one of the most sacred. An ancient law allowed only high-ranking tribal chiefs to visit its peak. Ancient Hawaiians living on the slopes of Mauna Kea relied on its extensive forests for food, and quarried the dense volcano-glacial basalts on its flanks for tool production. 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 mountain's ecology. Mauna Kea can be ecologically divided into three sections: an alpine climate at its summit, a Sophora chrysophylla–Myoporum sandwicense (or māmane–naio) forest on its flanks and an Acacia koa–Metrosideros polymorpha (or koa–ʻōhiʻa) forest, now mostly cleared by the former sugar industry, at its base. In recent years, concern over the vulnerability of the native species has led to court cases that have forced the Hawaii Department of Land and Natural Resources to eradicate all feral species on the mountain.
With its high altitude, dry environment, and stable airflow, Mauna Kea's summit is one of the best sites in the world for astronomical observation, and one of the most controversial. 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 scientific research across the electromagnetic spectrum from visible light to radio, and comprise one of the world's largest facilities of their type. Their construction on a "sacred landscape", replete with endangered species and ongoing cultural practices, continues to be a topic of debate and protest. Studies are underway to determine their effect on the summit ecology, particularly on the rare Wēkiu bug.
Read more about Mauna Kea: Geology, Summit Observatories, Climate, Recreation