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Typical shield volcanoes found in California and Oregon measure 3 to 4 mi (5 to 6 km) in diameter and 1,500 to 2,000 ft (500 to 600 m) in height, [6] while shield volcanoes in the central Mexican Michoacán–Guanajuato volcanic field average 340 m (1,100 ft) in height and 4,100 m (13,500 ft) in width, with an average slope angle of 9.4° and ...
Unlike shield volcanoes, they are characterized by a steep profile and periodic, often alternating, explosive eruptions and effusive eruptions. Some have collapsed craters called calderas . The central core of a stratocone is commonly dominated by a central core of intrusive rocks that range from around 500 meters (1,600 ft) to over several ...
A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers of hardened lava and tephra. [1] Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and explosive eruptions. [2] Some have collapsed summit craters called calderas. [3]
Cinder cones are also commonly found on the flanks of shield volcanoes, stratovolcanoes, and calderas. [3] For example, geologists have identified nearly 100 cinder cones on the flanks of Mauna Kea, a shield volcano located on the island of Hawaii. [3] Such cinder cones likely represent the final stages of activity of a mafic volcano. [11]
Volcanic rocks (often shortened to volcanics in scientific contexts) are rocks formed from lava erupted from a volcano. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks .
Mount Edziza, a large shield volcano in northwestern British Columbia. The most active volcanic region of the northern Pacific Northwest is called the Northern Cordilleran Volcanic Province (sometimes called the Stikine Volcanic Belt). It contains more than 100 young volcanoes and several eruptions known to have occurred within the last 400 years.
Formed of a complex of stratovolcanoes and shield volcanoes, [1] there are about 35 known satellite vents in the Mazama complex. [6] Mazama is surrounded by monogenetic cinder cones, lava fields, and shield volcanoes made up of calc-alkaline basalt and andesite, tholeiite, and shoshonitic andesite. Varying in age from 600,000 to 40,000 years ...
[1] [3] On shield volcanoes forming from level seafloor without neighboring vents, flank rifting occurs more evenly distributed around the vent. [1] However, where the flanks of a volcano may be supported on one side by the presence of a pre-existing feature, or burdened with various planes of weakness, rift zone formation promulgates according ...