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Biggest Volcano on Earth




Volcano :- ||Biggest Volcano on Earth||Top 10 Volcano on Earth|| For country wise volcano please visit above drop down menu


Which is the world's largest volcano?

The largest volcano on earth is Mauna Loa on Hawai'i Big Island. It is a massive shieldvolcano constructed by countless lava flows. When measured from the base to the top, the pile of lavas measures more than 17,000 m (56,000 ft)!

When measured from the sea floor, Mauna Loa's height is still more than 9,000 m, thus it is also the highest mountain on earth. Mauna Loa in fact is so heavy, that its weight has bent the oceanic crust under the volcano several kilometers downwards into the mantle.

Mauna Loa is one of the Earth's most active volcanoes, with 33 well-documented eruptions in historic times since 1843. Its last eruption was in 1984 and since 2004, Mauna Loa is showing increasing signs of a possible awakening in a not-too-distant future.



The biggest volcano in the world is Mauna Loa, a volcano on the big island of Hawaii. Mauna Loa is next to the biggest mountain in the world, Mauna Kea and both of these mountains along with other land masses form the actual island. This volcano is about 1,000,000 years old and is one of the most active volcanoes on the earth and from base to summit is almost 11,000 meters; the base being 13 kilometers under the ocean. In fact, the Hawaiian Islands were formed by volcanic activity.

Mauna Loa is a Shield volcano with gently sloping sides forming a large, gently sloping rocky mound. The lava oozes gently; comparatively, out of fissures in the earth. This is different from a Stratovolcano, like Mt. St. Helens that erupts in a spectacular explosion of lava and ash that travels high into the air. Mauna Loa last erupted in 1984.

Mauna Loa, and the Hawaiian Islands are on the Pacific tectonic plate, one of the 7 major plates on earth. Gradually, over time, the Pacific Plate will move away from the hotspot upon which it sits, and a new island chain will likely form when new rock is generated; in geologic time; hundreds of thousands of years, so no need to liquidate real estate in Hawaii just yet. Movement of these plates is responsible for volcanoes, earthquakes and tsunamis along with the formation of islands including Iceland. Plate tectonics are also responsible for massive mountain ranges like the Himalayan and Rocky Mountains. Plate tectonics caused the breakup of the massive land mass known as Pangaea. Ever notice how the continents look like they fit together like puzzle pieces? Well, they were once all part of a giant, continuous land mass. Plates floating on magma gradually began to separate into the continents that we know today. The Himalayan Mountains were formed when India, formerly an island, smashed up against Asia. Similarly, the Rocky Mountains were formed when a large floating landmass crushed against North America. I like the study of Plate Tectonics; very cool stuff.



Mauna Loa is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaiʻi in the Pacific Ocean, and the largest on Earth in terms of volume and area covered. It is an active shield volcano, with a volume estimated at approximately 18,000 cubic miles (75,000 km3), although its peak is about 120 feet (37 m) lower than that of its neighbor, Mauna Kea. The Hawaiian name "Mauna Loa" means "Long Mountain". Lava eruptions from Mauna Loa are silica-poor, and very fluid; eruptions tend to be non-explosive and the volcano has relatively shallow slopes.
Mauna Loa has probably been erupting for at least 700,000 years, and may have emerged above sea level about 400,000 years ago. The oldest-known dated rocks are not older than 200,000 years. The volcano's magma comes from the Hawaii hotspot, which has been responsible for the creation of the Hawaiian island chain over tens of millions of years. The slow drift of the Pacific Plate will eventually carry Mauna Loa away from the hotspot within 500,000 to one million years from now, at which point it will become extinct.
Mauna Loa's most recent eruption occurred from March 24, 1984, through April 15, 1984. No recent eruptions of the volcano have caused fatalities, but eruptions in 1926 and 1950 destroyed villages, and the city of Hilo is partly built on lava flows from the late 19th century. In view of the hazards it poses to population centers, Mauna Loa is part of the Decade Volcanoes program, which encourages studies of the most dangerous volcanoes. Mauna Loa has been intensively monitored by the Hawaiian Volcano Observatory since 1912. Observations of the atmosphere are undertaken at the Mauna Loa Observatory, and of the Sun at the Mauna Loa Solar Observatory, both located near its summit. Hawaii Volcanoes National Park covers the summit and the southeastern flank of the volcano, including a separate volcano, Kīlauea.


maua volcano

Origins

Mauna Loa began erupting between 700,000 and 1,000,000 years ago and has grown steadily since then. Like all of the Hawaiian islands, Mauna Loa has its origins in the Hawaii hotspot—a plume of magma rising from deep in the Earth's mantle. The hotspot remains in a fixed position, while the Pacific Plate drifts over it at a rate of about 4 inches (10 cm) per year. The upwelling of the hot magma creates volcanoes, and each individual volcano erupts for a few million years before the movement of the plate carries it away from the rising magma.
The hotspot has existed for at least 80 million years, and the Emperor Seamounts chain of old volcanoes stretches almost 3,600 miles (5,800 km) away from the hotspot. Currently, the hotspot feeds activity at five volcanoes: Mauna Loa, Kīlauea, and Hualālai on the Big Island, Haleakalā on Maui, and Loʻihi, a submarine volcano south of the Big Island and the youngest Hawaiian volcano. Mauna Loa is the largest of these, although Kīlauea is currently the site of the most intense volcanic activity.

Prehistoric eruptions

Prehistoric eruptions of Mauna Loa have been extensively analyzed by carrying out radiocarbon dating on fragments of charcoal found beneath lava flows. The mountain's prehistoric activity is probably the best known of any volcano. Studies have shown that a cycle occurs in which volcanic activity at the summit is dominant for several hundred years, after which activity shifts to the rift zones for several more centuries, and then back to the summit again. Two cycles have been clearly identified, each lasting 1,500–2,000 years. This cyclical behavior is unique to Mauna Loa among the Hawaiian volcanoes.
Records show that between about 7,000 and 6,000 years ago Mauna Loa was largely inactive. The cause of this cessation in activity is not known, and no known similar hiatus has been found at other Hawaiian volcanoes except for those currently in the post-shield stage. Between 11,000 and 8,000 years ago, activity was more intense than it is today. However, Mauna Loa's overall rate of growth has probably begun to slow over the last 100,000 years, and the volcano may in fact be nearing the end of its tholeiitic basalt shield-building phase.

Historic eruptions

Although Ancient Hawaiians had witnessed eruptions for many centuries, written records exist only for eruptions that have occurred since the early 19th century. The first historical eruption occurred in 1832, and since then 32 eruptions have been documented.
The typical pattern is for an eruption to start at Mokuʻāweoweo, then move to a focal vent lower on one of the rift zones. Often, a major rift eruption is preceded by a smaller event that is limited to Mokuʻāweoweo, a year or more before the larger one. The latter occurred in 1880, 1940, and 1949, before the massive flank eruptions of 1881, 1942, and 1950. In total, these eruptions have covered over 310 square miles (800 km2) of the volcano's flanks with lava flows. Typically, eruptions have been brief but intense, with 0.06 to 0.12 cubic miles (0.25–0.5 km³) of lava erupted over a few weeks.
The most prominent historic eruptions of Mauna Loa, with extensive lava flows in forest and agricultural areas, were in 1855, 1881, 1935, 1942, and 1950 on the northeast rift zone; 1887, 1907, 1916, 1919, 1926, and 1950 on the southwest rift zone; and the 1859 radial vent eruption.
An eruption in 1935 that headed toward the city of Hilo led to an unusual employment of air power. Five bombers of the 23d and 72d Bombardment Squadrons of the United States Air Force dropped bombs in the path of the lava in order to divert it away from Hilo. The eruption stopped six days later. The first flow extended 24 kilometers (15 mi) from the vent at 2,800 meters (9,200 ft) elevation to the ocean in only three hours during the night, and a second flow before dawn cut off the escape route for people in the village of Hoʻokena. The eruption eventually focused on a flow further to the south, which also reached the ocean.
On March 25, 1984 an eruption started: a small summit eruption was followed by a larger flank lava flow that threatened Hilo. Fissures opened to the northwest and southeast, from the summit down to 9,500 feet (2,900 m) above sea level. Flows from this eruption headed rapidly towards Hilo again, but stopped about 2.5 miles (4.0 km) from the outskirts when the eruption ended after three weeks.As of 2009, Mauna Loa has been inactive for over 25 years, its longest quiet period in recorded history.

 

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