![]() Eruptions occur along rift zones because they are areas of weakness, hence allow pathways for magma to travel within the volcanoes. Kīlauea’s rift zones are oriented parallel to the mobile southern flank that accommodates spreading and widening since Kīlauea is buttressed against Mauna Loa on its northern flank. The rift zones on Mauna Loa and Kīlauea contain vents, fissures, pit craters, spatter cones, cinder cones, and grabens. Rift zones and summit vents typically share the same magmatic source with magma moving laterally from the shallow magma chamber beneath the summit to feed rift eruptions. The presence of rift zones are responsible for these shield’s elongated shapes. Learn MoreĮruptions that occur along rift (fissure) zones are a major feature of some shield volcanoes, particularly the shield volcanoes that make up Hawai‘i. The Hawaiian shield volcanoes are the largest mountains on Earth.Mauna Kea Volcano rises 13,796 feet (4,205 meters) above sea level but extends about 19,700 feet (6,000 meters) below sea level to meet the deep ocean floor. The snow-capped Mauna Loa behind the active lava lake in the Halemaʻumaʻu pit crater in the Kīlauea caldera. They are built by repeated eruptions that occurred intermittently over vast periods of time (up to a million years or longer). Shield volcanoes are usually constructed almost entirely of basaltic and/or andesitic lava flows which were very fluid when erupted. ![]() Shield volcanoes are truly massive with volumes that dwarf other types of volcanoes, even large composite volcanoes. It likely emerged above sea level about 300,000 years ago, and it has grown rapidly upward. The volcanos earliest lava flows erupted onto the seafloor and submarine flanks of adjacent Huallai or Mauna Kea volcanoes between about 0.6 and 1 million years ago. Shield volcanoes have a convex shape as they are flatter near the summit. Scientists calculate Mauna Loas volume to be at least 75,000 km 3 (18,000 mi 3 ). ![]() Instead, they are broad volcanoes with gentle slopes and are shaped somewhat like a warrior’s shield lying flat on the Earth. With a summit elevation of 13,677 feet (4169 m) above sea level, Mauna Loa is more than 7,500 feet (2,280 m) in elevation higher than Kīlauea (4,091 feet 1,247 m).Īlthough shield volcanoes are the largest volcanoes on Earth, they do not form soaring mountains with conical peaks like composite volcanoes. ![]() If measured from its underwater base, Mauna Loa is almost twice the height of Mount Everest. It is the highest and most massive mountain on Earth. Mauna Loa means Long Mountain in Hawaiian. The broad shield of Mauna Loa (in the background) rising above the Kīlauea caldera in the foreground. Like Kilauea, Mauna Loa is a shield volcano, a huge, gently sloping mountain built up of many eruptions of highly fluid lava. ![]()
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