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Mauna Loa Volcano, Hawaii, a shield volcano, as viewed from the summit of Kilauea, about 33 miles to the southeast.
Mauna Loa, on the Big Island of Hawaii, is the largest active volcano in the world. It last erupted in 1984.
Mauna Loa erupted 14 times in the 20th Century, and 37 times since 1832.
Mauna Loa is the most massive mountain on Earth, rising to an elevation of 13,677 feet above sea level, or 31,677 feet above the sea floor.
Its volume is 10,000 miles3.
The tallest mountain on Earth is located nearby, also on the Big Island of Hawaii. It is Mauna Kea, rising to an elevation of 13,796 feet above sea level, or 31,796 feet above the sea floor.
Both Mauna Loa and Mauna Kea are shield volcanoes.
In comparison, Mt. Everest (in the Himalayas), the highest point on Earth above sea level, rises to an elevation of 8848 m (or 29,028 ft). Mt. Everest is NOT a volcano, however.
The largest volcano in the Solar System is also a shiled volcano. It is located on the planet Mars. Its name is Olympus Mons (or Mount Olympus), and it is three times as high as the largest volcanoes on Earth (nearly 27 km high). It is about 100 times as massive as one of the Hawaiian volcanoes.
Cinder cone, Puu Puai, created by eruption in 1959, Devastation Trail, Kilauea, Hawaii Volcanoes National Park.
The volcano Paracutin, in Mexico, is a well-known example of a cinder cone.
Eruption of Mt. St. Helens
large (1 - 10 km across)
layered structure, consisting of alternating layers of lava and pyroclastic material
high silica content (sialic or intermediate) with composition of andesite, dacite, and occasionally rhyolite
These volcanoes make up the largest perentage of the Earth's volcanoes (about 60%)
Examples: Mt. Vesuvius, Cascade Range volcanoes such as Mt. St. Helens and Mt. Ranier
Shapes of volcanoes are due to the viscosity of the magma (or lava).
Runny basaltic lava will not form a steep cone; forms relatively flat shield volcanoes.
Mafic lavas are low in silica (only about 50% SiO2)
Sialic lavas may have more than 70% SiO2.
Explosivity of the volcano is also controlled by the viscosity (and chemistry) of the lava or magma.
Gases are easily released from low viscosity (runny) lavas.
Ex. = vesicular basalt.
Looking into Caldera of Kilauea Volcano, which is about 2 to 2.5 miles in diameter, and about 400 feet deep. A road around the crater rim is 11 miles long. Steam is rising from the inner crater, Halema'uma'u, near the center of the left photo.
Kilauea is the world's most active volcano, and it has been erupting continuously since January 3, 1983, with lobes of lava threatening (and destroying) housing subdivisions, and entering the sea through lava tubes.
Kilauea rarely erupts from its summit. Instead it erupts from vents on its flanks, particularly along its east and southwest rift zones.
The summit of Kilauea is about 4000 feet above sea level.
See explanatory diagram of Kilauea caldera on sign at Volcanoes National Park.
Pahoehoe flows (from circa 1993) near Kalapana Black Sand Beach.
Pahoehoe at the end of Chain of Craters Road (from circa 1995).
Weathered aa lava flow, Kalapana Region, Big Island of Hawaii
1974 Aa lava flow, Chain of Craters Road, Hawaiian Volcanoes National Park.
Pyroclastic material from Kilauea volcano, Hawaii.
Olivine crystals (green) and Pele's Tears (black oval) in pyroclastic debris along Devastation Trail, Hawaii Volcanoes National Park. (In the palm of a hand.)
Between 100 and 2000 metric tons of sulfur dioxide (SO2) are released per day from Kilauea. The rain is so acidic that a desert has formed downwind from the summit of the volcano.
Sulfur Banks, Hawaii Volcanoes National Park. Sulfur and other minerals are being deposited here from gases rising from the hot magma below. The steam contains mostly water vapor, with lesser amounts of carbon dioxide and hydrogen sulfide.
Warning signs about gases in Hawaii Volcanoes National Park.
A nuee ardente from Mount Pelee, on the Caribbean island of
Martinique, destroyed the town of St. Pierre in 1902, killing almost all of its 28,000 inhabitants at once
(a prisoner in a dungeon, a shoemaker, and a few people on ships in the harbor survived).
Volcano diagrams used with permission of Bruce E. Herbert, Texas A & M University, Big Bend Virtual Field Trip
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This page created by
Pamela J. W. Gore
Georgia Perimeter College, Clarkston Campus, Clarkston, GA
Modified March 4, 1998
Modified September 21, 1998
Modified July 17, 1999
Modified May 12, 2000
Modified June 4, 2000
Modified February 24, 2001