Mauna Kea is a dormant shield volcano that is located on the island of Hawaii and reaches an elevation of 13,803 feet. It is one of five volcanoes that comprise the island and is thought to be about one million years old. Mauna Kea, like all Hawaiian volcanoes, was created when the Pacific tectonic plate passed over a volcanic hotspot. The Hawaiian volcanoes, which extend over an area known as the Hawaiian Ridge – Emperor Seamount chain, have been well studied, but it is not known how the hotspot was created. Its last eruption occurred about 4,600 years ago and it is thought to be capable of erupting in the future.
The first settlers to reach Hawaii remained on the coastline, where there was an abundance of food, moving into the areas surround Mauna Kea and Mauna Loa in the Twelfth and Thirteenth centuries. Studies have shown that these areas provided a new food source to the settlers, as well as stones for tools. Evidence also suggests that area provided a place for navigation or astrological observation and spiritual practices. Because the island was not previously inhabited by humans, the settlers negatively impacted the ecosystem.
The forest along the coastline was converted to grassland and many species became extinct, especially various species of bird. It is thought that the extinctions and changes in landscape were primarily caused the introduction of the Polynesian rat. Other animals were eventually brought to the island, including cattle, which further damaged its ecosystems. Today, there are only 1,000 native plant species on the island and over 4,600 species of non-native plants. Some native animal species include the Wēkiu bug, the Hawaiian Hoary bat, and the Hawaiian crow.
Because Mauna Kea was considered sacred, along with the other four volcanoes, only the most high-ranking tribal chiefs could ascend to its summit. The first recorded outsider to reach the summit was Joseph F. Goodrich, who climbed the volcano in 1823. He noted that an arrangement of stones found on the summit most likely meant that he was not the first to reach it and also recorded four different ecosystems during his ascent including alpine tundra at the summit and māmane-naio forests below the summit, of which 52,500 acres are protected as the Mauna Kea Forest Reserve.
The lava flows found on Mauna Kea are mixed with those from other volcanoes, including flows from Kohala to the northwest and Mauna Loa to the south. The rift zones, or eruptive fissures, from the shield stage of Maua Kea are no longer visible, but the lava that flowed from these fissures are comprised of tholeiitic basalts, while the lava flows from its post-shield stage, after it completed the formation of its current cone, are comprised of hawaiites and mugearites. This volcano is the only on the island to display strong evidence of glaciation, which affected the shape of many features over a period of 180,000 years.
Mauna Kea is a popular tourist area that provides visitors and inhabitants of the island many activities, including mountain climbing and hiking, although climbing to the summit of the volcano is difficult due to cold weather and high elevation. Some skiing does occur between the months of January and February when weather permits, although there are no facilities that support this activity. The rugged coasts of Mauna Kea offer many recreation areas including Wailuku River State Park, Kalopa State Recreation Area, and Akaka Falls State Park. Its summit provides one of the best areas in the world for astronomical observation because it is dry, clear, and devoid of air and light pollution.