Mauna Loa is an active volcano in the Hawaiian Islands, one of five volcanic peaks that together form the Island of Hawaii. In Hawaiian mauna loa means "long mountain". It is Earth's largest volcano and is the exposed (subareal) part of an enormous mid-ocean mountain. As such it is also the Earth's tallest mountain (17 km or 56,000 ft) if measured from its base on the mid-ocean floor to the highest point at 13,680 ft (4,170 m) above sea level.
There have been some 33 eruptions of Mauna Loa in historical time, the last in March-April, 1984.
The elevation and location of Mauna Loa have made it an important location for atmospheric and other scientific observations. The Mauna Loa Solar Observatory has long been prominent in observations of the Sun.
See also: List of volcanoes