Located in the island of Hawaii, Mauna Loa is considered as the biggest active volcano in the world. Rising to a height of 13,680 feet (4, 170 meters) above sea level, its name fittingly means “Long Mountain” in the Hawaiian dialect. It has a length of 60 miles and a width of 30 miles, taking up half of the whole island itself.
Sitting on ocean floor measuring a depth of roughly 16,400 feet (5,000 meters), Mauna Loa’s height in relation to the sea floor would actually be in the region of 30,080 feet (9,170 meters). Not only would this make it the world’s biggest active volcano, it could also be considered as one of the world’s tallest mountains, even though most mountains like Mount Everest in the Himalayas sit higher in proportion with sea level.
Also, the massive weight of a large land mass such as a mountain would press down against the Earth’s crust. Thus, the sea floor upon which Mauna Loa rests is pushed down by 26,000 feet (8,000 meters) more. Hence, to determine the thickness at the center of the pile of lava that comprises Mauna Loa, its height above sea level would have to be added to its sea-level-to-sea-floor height and the breadth of its indention in the Pacific ocean floor, to come up with a total of 56,080 feet (17,170 meters).
Mauna Loa is referred to as a shield volcano because of its shield-like shape. Basically, it has gently sloping sides due to the typically fluid flow of its lava. It has been estimated that the volcano started erupting between 700,000-1,000,000 years ago, and remains active to this day. The majority of Mauna Loa’s eruptions have taken place at its summit, as well as in 2 rift zones that extend north-east and south-west of the summit. The volcano’s main volcanic center is the crater at its summit, known as Moku’aweoweo. This crater has a diameter of 1.75-3 miles, and is estimated to have been created 1,000 to 1,500 years in the past as the result of a very powerful eruption that occurred in the north-east rift zone.
There have been 33 recorded Mauna Loa eruptions, a statistic that the world’s biggest volcano has in common with the world’s smallest, the Taal Volcano in the Philippines. The earliest recorded eruption of Mauna Loa occurred in 1780, a short time following Captain Cook’s arrival to the Hawaiian Islands. An eruption that took place in 1868 caused a magnitude 8 earthquake, the largest one ever recorded in Hawaii. The last recorded eruption to date lasted from March 24 to April 15, 1984. Mauna Loa has remained relatively dormant since then, but its activity is evinced by its constant lava flows. Nevertheless, there is always the ever-present threat that the volcano will erupt again sometime in the future.