{"id":340,"date":"2015-07-10T22:37:33","date_gmt":"2015-07-10T22:37:33","guid":{"rendered":"https:\/\/courses.candelalearning.com\/earthscienceck12\/?post_type=chapter&#038;p=340"},"modified":"2015-07-10T23:01:36","modified_gmt":"2015-07-10T23:01:36","slug":"types-of-volcanoes","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/chapter\/types-of-volcanoes\/","title":{"raw":"Types of Volcanoes","rendered":"Types of Volcanoes"},"content":{"raw":"<body>\n    <h2>\n      Lesson Objectives\n    <\/h2>\n    <ul>\n<li>Describe the basic shapes of volcanoes.\n      <\/li>\n      <li>Compare the features of volcanoes.\n      <\/li>\n      <li>Describe the stages in the formation of volcanoes.\n      <\/li>\n    <\/ul>\n<h2>\n      Vocabulary\n    <\/h2>\n    <ul>\n<li>caldera\n      <\/li>\n      <li>cinder cone\n      <\/li>\n      <li>composite volcano\n      <\/li>\n      <li>shield volcano\n      <\/li>\n      <li>supervolcano\n      <\/li>\n    <\/ul>\n<h2>\n      Introduction\n    <\/h2>\n    <p>\n      A volcano is a vent through which molten rock and gas escape from a magma chamber. Volcanoes differ in many features such as height, shape, and slope steepness. Some volcanoes are tall cones and others are just cracks in the ground (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDgtMjQtTXQtaGVsZW5zLmpwZw..\">below<\/a>). As you might expect, the shape of a volcano is related to the composition of its magma.\n    <\/p>\n    <div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Left: Courtesy of DR Mullineaux\/US Geological Survey; Right: Courtesy of Lyn Topinka\/US Geological Survey\" --><!-- @@url=\"Left: http:\/\/volcanoes.usgs.gov\/volcanoes\/st_helens\/st_helens_gallery_29.html; Right: http:\/\/commons.wikimedia.org\/wiki\/File:MSH82_st_helens_plume_from_harrys_ridge_05-19-82.jpg\" --><!-- @@license=\"Public Domain\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223602\/201412291419878414503301_127e29ae4e9b5cfbaf00be905c13ae01-201412291419879765995387.jpg\" title=\"\" longdesc=\"Mount%20St.%20Helens%20was%20a%20beautiful%2C%20classic%2C%20cone-shaped%20volcano.%20The%20volcano%26%238217%3Bs%201980%20eruption%20blew%20more%20than%20400%20meters%20%281%2C300%20feet%29%20off%20the%20top%20of%20the%20mountain.%20\" alt=\"\" id=\"x-ck12-SFMtRVMtMDgtMjQtTXQtaGVsZW5zLmpwZw..\"><\/p>\n      <p>\n        Mount St. Helens was a beautiful, classic, cone-shaped volcano. The volcano\u2019s 1980 eruption blew more than 400 meters (1,300 feet) off the top of the mountain.\n      <\/p>\n    <\/div>\n    <h2>\n      Composite Volcanoes\n    <\/h2>\n    <p>\n      <strong>Composite volcanoes<\/strong> are made of felsic to intermediate rock. The viscosity of the lava means that eruptions at these volcanoes are often explosive (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDMtMDEuanBn\">below<\/a>).\n    <\/p>\n    <div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Chris Moore\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Fujifrommarubun.jpg\" --><!-- @@license=\"The copyright holder of this work allows anyone to use it for any purpose including unrestricted redistribution, commercial use, and modification\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223604\/201412291419878414526609_4db842ff83ef87d52f99067c09b8717b-201412291419879766678895.jpg\" title=\"\" longdesc=\"Mt.%20Fuji%2C%20the%20highest%20mountain%20in%20Japan%2C%20is%20a%20dormant%20composite%20volcano.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDMtMDEuanBn\"><\/p>\n      <p>\n        Mt. Fuji, the highest mountain in Japan, is a dormant composite volcano.\n      <\/p>\n    <\/div>\n    <p>\n      The viscous lava cannot travel far down the sides of the volcano before it solidifies, which creates the steep slopes of a composite volcano. Viscosity also causes some eruptions to explode as ash and small rocks. The volcano is constructed layer by layer, as ash and lava solidify, one upon the other (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDEtMDIuanBn\">below<\/a>). The result is the classic cone shape of composite volcanoes.\n    <\/p>\n    <div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Zachary Wilson\" --><!-- @@url=\"CK-12 Foundation\" --><!-- @@license=\"CC BY-NC 3.0\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223605\/201412291419878414546583_e93bb281f4576950b28c530de5a2aab8-201412291419879767532525.png\" title=\"\" longdesc=\"A%20cross%20section%20of%20a%20composite%20volcano%20reveals%20alternating%20layers%20of%20rock%20and%20ash%3A%20%281%29%20magma%20chamber%2C%20%282%29%20bedrock%2C%20%283%29%20pipe%2C%20%284%29%20ash%20layers%2C%20%285%29%20lava%20layers%2C%20%286%29%20lava%20flow%2C%20%287%29%20vent%2C%20%288%29%20lava%2C%20%289%29%20ash%20cloud.%20%20Frequently%20there%20is%20a%20large%20crater%20at%20the%20top%20from%20the%20last%20eruption.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDEtMDIuanBn\"><\/p>\n      <p>\n        A cross section of a composite volcano reveals alternating layers of rock and ash: (1) magma chamber, (2) bedrock, (3) pipe, (4) ash layers, (5) lava layers, (6) lava flow, (7) vent, (8) lava, (9) ash cloud. Frequently there is a large crater at the top from the last eruption.\n      <\/p>\n    <\/div>\n    <h2>\n      Shield Volcanoes\n    <\/h2>\n    <p>\n      <strong>Shield volcanoes<\/strong> get their name from their shape. Although shield volcanoes are not steep, they may be very large. Shield volcanoes are common at spreading centers or intraplate hot spots (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDMtMDM.\">below<\/a>).\n    <\/p>\n    <div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Nathan Forget\" --><!-- @@url=\"http:\/\/www.flickr.com\/photos\/nathanf\/5999830480\/\" --><!-- @@license=\"CC BY 2.0\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223607\/201412291419878414565220_9ae46b2c51ed9e410135c78c960e99c9-201412291419879768110227.jpg\" title=\"\" longdesc=\"Mauna%20Loa%20Volcano%20in%20Hawaii%20%28in%20the%20background%29%20is%20the%20largest%20shield%20volcano%20on%20Earth%20with%20a%20diameter%20of%20more%20than%20112%20kilometers%20%2870%20miles%29.%20The%20volcano%20forms%20a%20significant%20part%20of%20the%20island%20of%20Hawaii.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDMtMDM.\"><\/p>\n      <p>\n        Mauna Loa Volcano in Hawaii (in the background) is the largest shield volcano on Earth with a diameter of more than 112 kilometers (70 miles). The volcano forms a significant part of the island of Hawaii.\n      <\/p>\n    <\/div>\n    <p>\n      The lava that creates shield volcanoes is fluid and flows easily. The spreading lava creates the shield shape. Shield volcanoes are built by many layers over time and the layers are usually of very similar composition. The low viscosity also means that shield eruptions are non-explosive.\n    <\/p>\n    <p>\n      This <em>Volcanoes 101<\/em> video from National Geographic discusses where volcanoes are found and what their properties come from <strong>(3e)<\/strong>: <a href=\"http:\/\/www.youtube.com\/watch?v=uZp1dNybgfc\">http:\/\/www.youtube.com\/watch?v=uZp1dNybgfc<\/a> (3:05).\n    <\/p>\n    <div itemprop=\"video\" itemscope=\"\" itemtype=\"http:\/\/schema.org\/VideoObject\">\n       \n\nhttps:\/\/www.youtube.com\/watch?v=uZp1dNybgfc\n\n    <\/div>\n    <h2>\n      Cinder Cones\n    <\/h2>\n    <p>\n      <strong>Cinder cones<\/strong> are the most common type of volcano. A cinder cone has a cone shape, but is much smaller than a composite volcano. Cinder cones rarely reach 300 meters in height but they have steep sides. Cinder cones grow rapidly, usually from a single eruption cycle (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDMtMDU.\">below<\/a>). Cinder cones are composed of small fragments of rock, such as pumice, piled on top of one another. The rock shoots up in the air and doesn\u2019t fall far from the vent. The exact composition of a cinder cone depends on the composition of the lava ejected from the volcano. Cinder cones usually have a crater at the summit.\n    <\/p>\n    <div class=\"x-ck12-img-thumbnail x-ck12-nofloat\">\n      <!-- @@author=\"Courtesy of K Segerstrom\/US Geological Survey\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Paricutin_30_612.jpg\" --><!-- @@license=\"Public Domain\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223608\/201412291419878414581466_ce6ef40ffeb8aeaaca579432d40d5871-201412291419879768751411.jpg\" title=\"\" longdesc=\"In%201943%2C%20a%20Mexican%20farmer%20first%20witnessed%20a%20cinder%20cone%20erupting%20in%20his%20field.%20In%20a%20year%2C%20Paricut%26%23237%3Bn%20was%20336%20meters%20high.%20By%201952%2C%20it%20reached%20424%20meters%20and%20then%20stopped%20erupting.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDMtMDU.\"><\/p>\n      <p>\n        In 1943, a Mexican farmer first witnessed a cinder cone erupting in his field. In a year, Paricut\u00edn was 336 meters high. By 1952, it reached 424 meters and then stopped erupting.\n      <\/p>\n    <\/div>\n    <p>\n      Cinder cones are often found near larger volcanoes (<strong>Figure<\/strong> <a href=\"#x-ck12-RVMtMDItMDEtMDYuanBn\">below<\/a>).\n    <\/p>\n    <div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Courtesy of NASA's Earth Observatory\" --><!-- @@url=\"http:\/\/earthobservatory.nasa.gov\/IOTD\/view.php?id=6585\" --><!-- @@license=\"Public Domain\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223609\/201412291419878414666914_1341117cfdfa4167528a7f3e16e7fcf4-201412291419879769414201.jpg\" title=\"\" longdesc=\"This%20Landsat%20image%20shows%20the%20topography%20of%20San%20Francisco%20Mountain%2C%20an%20extinct%20volcano%2C%20with%20many%20cinder%20cones%20near%20it%20in%20northern%20Arizona.%20Sunset%20crater%20is%20a%20cinder%20cone%20that%20erupted%20about%201%2C000%20years%20ago.%20\" alt=\"\" id=\"x-ck12-RVMtMDItMDEtMDYuanBn\"><\/p>\n      <p>\n        This Landsat image shows the topography of San Francisco Mountain, an extinct volcano, with many cinder cones near it in northern Arizona. Sunset crater is a cinder cone that erupted about 1,000 years ago.\n      <\/p>\n    <\/div>\n    <h2>\n      Supervolcanoes\n    <\/h2>\n    <p>\n      <strong>Supervolcano<\/strong> eruptions are extremely rare in Earth history. It\u2019s a good thing because they are unimaginably large. A supervolcano must erupt more than 1,000 cubic km (240 cubic miles) of material, compared with 1.2 km<sup>3<\/sup> for Mount St. Helens or 25 km<sup>3<\/sup> for Mount Pinatubo, a large eruption in the Philippines in 1991. Not surprisingly, supervolcanoes are the most dangerous type of volcano.\n    <\/p>\n    <p>\n      Supervolcanoes are a fairly new idea in volcanology. The exact cause of supervolcano eruptions is still debated. However, scientists think that a very large magma chamber erupts entirely in one catastrophic explosion. This creates a huge hole or <strong>caldera<\/strong> into which the surface collapses (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDMtMDY.\">below<\/a>).\n    <\/p>\n    <div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Courtesy of NASA\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Santorini_Landsat.jpg\" --><!-- @@license=\"Public Domain\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223610\/201412291419878414699012_1d05010df93693ce2f9981534a123e1a-201412291419879770063868.jpg\" title=\"\" longdesc=\"The%20caldera%20at%20Santorini%20in%20Greece%20is%20so%20large%20that%20it%20can%20only%20be%20seen%20by%20satellite.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDMtMDY.\"><\/p>\n      <p>\n        The caldera at Santorini in Greece is so large that it can only be seen by satellite.\n      <\/p>\n    <\/div>\n    <p>\n      The largest supervolcano in North America is beneath Yellowstone National Park in Wyoming. Yellowstone sits above a hotspot that has erupted catastrophically three times: 2.1 million, 1.3 million, and 640,000 years ago. Yellowstone has produced many smaller (but still enormous) eruptions more recently (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDgtMzEtWWVsbG93c3RvbmVfQ2FsZGVyYS5wbmc.\">below<\/a>). Fortunately, current activity at Yellowstone is limited to the region\u2019s famous geysers.\n    <\/p>\n    <div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"User:Kbh3rd\/Wikimedia Commons\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Yellowstone_Caldera.svg\" --><!-- @@license=\"Public Domain\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223611\/201412291419878414717977_21942f7c37cdf502f1b7c38b6ad16a3b-201412291419879770501395.png\" title=\"\" longdesc=\"The%20Yellowstone%20hotspot%20has%20produced%20enormous%20felsic%20eruptions.%20The%20Yellowstone%20caldera%20collapsed%20in%20the%20most%20recent%20super%20eruption.%20\" alt=\"\" id=\"x-ck12-SFMtRVMtMDgtMzEtWWVsbG93c3RvbmVfQ2FsZGVyYS5wbmc.\"><\/p>\n      <p>\n        The Yellowstone hotspot has produced enormous felsic eruptions. The Yellowstone caldera collapsed in the most recent super eruption.\n      <\/p>\n    <\/div>\n    <p>\n      Long Valley Caldera, south of Mono Lake in California, is the second largest supervolcano in North America (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDgtMzItTG9uZy1WYWxsZXktQ2FsZGVyYQ..\">below<\/a>). Long Valley had an extremely hot and explosive rhyolite about 700,000 years ago. An earthquake swarm in 1980 alerted geologists to the possibility of a future eruption, but the quakes have since calmed down.\n    <\/p>\n    <div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Image copyright Doug James, 2014\" --><!-- @@url=\"http:\/\/www.shutterstock.com\" --><!-- @@license=\"Used under license from Shutterstock.com\" -->\n      <p>\n        <img src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223614\/201412291419878414745420_94aa6363dd903997e88874ddf7089b3f-201412291419879771108680.jpg\" title=\"\" longdesc=\"The%20hot%20water%20that%20gives%20Hot%20Creek%2C%20California%2C%20its%20name%20is%20heated%20by%20hot%20rock%20below%20Long%20Valley%20Caldera.%20\" alt=\"\" id=\"x-ck12-SFMtRVMtMDgtMzItTG9uZy1WYWxsZXktQ2FsZGVyYQ..\"><\/p>\n      <p>\n        The hot water that gives Hot Creek, California, its name is heated by hot rock below Long Valley Caldera.\n      <\/p>\n    <\/div>\n    <ul>\n<li>An interactive image of the geological features of Long Valley Caldera is available here:\n      <\/li>\n    <\/ul>\n<p>\n      <a href=\"http:\/\/www.iris.edu\/hq\/files\/programs\/education_and_outreach\/aotm\/interactive\/B&amp;R_LongValleyCaldera.swf\">http:\/\/www.iris.edu\/hq\/files\/programs\/education_and_outreach\/aotm\/interactive\/B&amp;R_LongValleyCaldera.swf<\/a>\n    <\/p>\n    <p>\n      A supervolcano could change life on Earth as we know it. Ash could block sunlight so much that photosynthesis would be reduced and global temperatures would plummet. Volcanic eruptions could have contributed to some of the mass extinctions in our planet\u2019s history. No one knows when the next super eruption will be.\n    <\/p>\n    <p>\n      Interesting volcano videos are seen on National Geographic Videos, Environment Video, Natural Disasters, Earthquakes: <a href=\"http:\/\/video.nationalgeographic.com\/video\/player\/environment\/\">http:\/\/video.nationalgeographic.com\/video\/player\/environment\/<\/a>. One interesting one is \u201cMammoth Mountain,\u201d which explores Hot Creek and the volcanic area it is a part of in California.\n    <\/p>\n    <h2>\n      Lesson Summary\n    <\/h2>\n    <ul>\n<li>Composite, shield, cinder cones, and supervolcanoes are the main types of volcanoes.\n      <\/li>\n      <li>Composite volcanoes are tall, steep cones that produce explosive eruptions.\n      <\/li>\n      <li>Shield volcanoes form very large, gently sloped mounds from effusive eruptions.\n      <\/li>\n      <li>Cinder cones are the smallest volcanoes and result from accumulation of many small fragments of ejected material.\n      <\/li>\n      <li>An explosive eruption may create a caldera, a large hole into which the mountain collapses.\n      <\/li>\n      <li>Supervolcano eruptions are devastating but extremely rare in Earth history.\n      <\/li>\n    <\/ul>\n<h2>\n      Review Questions\n    <\/h2>\n    <ol id=\"x-ck12-OGUzZWNmOWFkYjhmZmJkYTZhMTdiZThmNDk4OWMxNjg.-mqu\" class=\"x-ck12-decimal\">\n<li>Rank, in order, the four types of volcanoes from smallest to largest in diameter.\n      <\/li>\n      <li>What factor best determines what type of volcano will form in a given area?\n      <\/li>\n      <li>Which type of volcano is most common?\n      <\/li>\n      <li>Why do pahoehoe and a\u2019a lava erupt from shield volcanoes? Why don't they erupt from composite volcanoes?\n      <\/li>\n      <li>Why are cinder cones short-lived?\n      <\/li>\n      <li>If supervolcanoes are so big, why did it take so long for scientists to discover them?\n      <\/li>\n    <\/ol>\n<h2>\n      Points to Consider\n    <\/h2>\n    <ul>\n<li>Composite volcanoes and volcanic cones usually have craters on the top. Why are the craters sometimes U- or horseshoe-shaped?\n      <\/li>\n      <li>Think about plate boundaries again. What type of volcanoes do you think are found at convergent, divergent, and transform boundaries? How about at intraplate sites?\n      <\/li>\n      <li>Some people have theorized that if a huge asteroid hits the Earth, the results would be catastrophic. How might an asteroid impact and a supervolcano eruption be similar?\n      <\/li>\n    <\/ul>\n<\/body>","rendered":"<h2>\n      Lesson Objectives<br \/>\n    <\/h2>\n<ul>\n<li>Describe the basic shapes of volcanoes.\n      <\/li>\n<li>Compare the features of volcanoes.\n      <\/li>\n<li>Describe the stages in the formation of volcanoes.\n      <\/li>\n<\/ul>\n<h2>\n      Vocabulary<br \/>\n    <\/h2>\n<ul>\n<li>caldera\n      <\/li>\n<li>cinder cone\n      <\/li>\n<li>composite volcano\n      <\/li>\n<li>shield volcano\n      <\/li>\n<li>supervolcano\n      <\/li>\n<\/ul>\n<h2>\n      Introduction<br \/>\n    <\/h2>\n<p>\n      A volcano is a vent through which molten rock and gas escape from a magma chamber. Volcanoes differ in many features such as height, shape, and slope steepness. Some volcanoes are tall cones and others are just cracks in the ground (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDgtMjQtTXQtaGVsZW5zLmpwZw..\">below<\/a>). As you might expect, the shape of a volcano is related to the composition of its magma.\n    <\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Left: Courtesy of DR Mullineaux\/US Geological Survey; Right: Courtesy of Lyn Topinka\/US Geological Survey\" --><!-- @@url=\"Left: http:\/\/volcanoes.usgs.gov\/volcanoes\/st_helens\/st_helens_gallery_29.html; Right: http:\/\/commons.wikimedia.org\/wiki\/File:MSH82_st_helens_plume_from_harrys_ridge_05-19-82.jpg\" --><!-- @@license=\"Public Domain\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223602\/201412291419878414503301_127e29ae4e9b5cfbaf00be905c13ae01-201412291419879765995387.jpg\" title=\"\" longdesc=\"Mount%20St.%20Helens%20was%20a%20beautiful%2C%20classic%2C%20cone-shaped%20volcano.%20The%20volcano%26%238217%3Bs%201980%20eruption%20blew%20more%20than%20400%20meters%20%281%2C300%20feet%29%20off%20the%20top%20of%20the%20mountain.%20\" alt=\"\" id=\"x-ck12-SFMtRVMtMDgtMjQtTXQtaGVsZW5zLmpwZw..\" \/><\/p>\n<p>\n        Mount St. Helens was a beautiful, classic, cone-shaped volcano. The volcano\u2019s 1980 eruption blew more than 400 meters (1,300 feet) off the top of the mountain.\n      <\/p>\n<\/p><\/div>\n<h2>\n      Composite Volcanoes<br \/>\n    <\/h2>\n<p>\n      <strong>Composite volcanoes<\/strong> are made of felsic to intermediate rock. The viscosity of the lava means that eruptions at these volcanoes are often explosive (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDMtMDEuanBn\">below<\/a>).\n    <\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Chris Moore\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Fujifrommarubun.jpg\" --><!-- @@license=\"The copyright holder of this work allows anyone to use it for any purpose including unrestricted redistribution, commercial use, and modification\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223604\/201412291419878414526609_4db842ff83ef87d52f99067c09b8717b-201412291419879766678895.jpg\" title=\"\" longdesc=\"Mt.%20Fuji%2C%20the%20highest%20mountain%20in%20Japan%2C%20is%20a%20dormant%20composite%20volcano.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDMtMDEuanBn\" \/><\/p>\n<p>\n        Mt. Fuji, the highest mountain in Japan, is a dormant composite volcano.\n      <\/p>\n<\/p><\/div>\n<p>\n      The viscous lava cannot travel far down the sides of the volcano before it solidifies, which creates the steep slopes of a composite volcano. Viscosity also causes some eruptions to explode as ash and small rocks. The volcano is constructed layer by layer, as ash and lava solidify, one upon the other (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDEtMDIuanBn\">below<\/a>). The result is the classic cone shape of composite volcanoes.\n    <\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Zachary Wilson\" --><!-- @@url=\"CK-12 Foundation\" --><!-- @@license=\"CC BY-NC 3.0\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223605\/201412291419878414546583_e93bb281f4576950b28c530de5a2aab8-201412291419879767532525.png\" title=\"\" longdesc=\"denied:A%20cross%20section%20of%20a%20composite%20volcano%20reveals%20alternating%20layers%20of%20rock%20and%20ash%3A%20%281%29%20magma%20chamber%2C%20%282%29%20bedrock%2C%20%283%29%20pipe%2C%20%284%29%20ash%20layers%2C%20%285%29%20lava%20layers%2C%20%286%29%20lava%20flow%2C%20%287%29%20vent%2C%20%288%29%20lava%2C%20%289%29%20ash%20cloud.%20%20Frequently%20there%20is%20a%20large%20crater%20at%20the%20top%20from%20the%20last%20eruption.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDEtMDIuanBn\" \/><\/p>\n<p>\n        A cross section of a composite volcano reveals alternating layers of rock and ash: (1) magma chamber, (2) bedrock, (3) pipe, (4) ash layers, (5) lava layers, (6) lava flow, (7) vent, (8) lava, (9) ash cloud. Frequently there is a large crater at the top from the last eruption.\n      <\/p>\n<\/p><\/div>\n<h2>\n      Shield Volcanoes<br \/>\n    <\/h2>\n<p>\n      <strong>Shield volcanoes<\/strong> get their name from their shape. Although shield volcanoes are not steep, they may be very large. Shield volcanoes are common at spreading centers or intraplate hot spots (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDMtMDM.\">below<\/a>).\n    <\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Nathan Forget\" --><!-- @@url=\"http:\/\/www.flickr.com\/photos\/nathanf\/5999830480\/\" --><!-- @@license=\"CC BY 2.0\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223607\/201412291419878414565220_9ae46b2c51ed9e410135c78c960e99c9-201412291419879768110227.jpg\" title=\"\" longdesc=\"Mauna%20Loa%20Volcano%20in%20Hawaii%20%28in%20the%20background%29%20is%20the%20largest%20shield%20volcano%20on%20Earth%20with%20a%20diameter%20of%20more%20than%20112%20kilometers%20%2870%20miles%29.%20The%20volcano%20forms%20a%20significant%20part%20of%20the%20island%20of%20Hawaii.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDMtMDM.\" \/><\/p>\n<p>\n        Mauna Loa Volcano in Hawaii (in the background) is the largest shield volcano on Earth with a diameter of more than 112 kilometers (70 miles). The volcano forms a significant part of the island of Hawaii.\n      <\/p>\n<\/p><\/div>\n<p>\n      The lava that creates shield volcanoes is fluid and flows easily. The spreading lava creates the shield shape. Shield volcanoes are built by many layers over time and the layers are usually of very similar composition. The low viscosity also means that shield eruptions are non-explosive.\n    <\/p>\n<p>\n      This <em>Volcanoes 101<\/em> video from National Geographic discusses where volcanoes are found and what their properties come from <strong>(3e)<\/strong>: <a href=\"http:\/\/www.youtube.com\/watch?v=uZp1dNybgfc\">http:\/\/www.youtube.com\/watch?v=uZp1dNybgfc<\/a> (3:05).\n    <\/p>\n<div itemprop=\"video\" itemscope=\"itemscope\" itemtype=\"http:\/\/schema.org\/VideoObject\">\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Volcano 101 | National Geographic\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/uZp1dNybgfc?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p><\/div>\n<h2>\n      Cinder Cones<br \/>\n    <\/h2>\n<p>\n      <strong>Cinder cones<\/strong> are the most common type of volcano. A cinder cone has a cone shape, but is much smaller than a composite volcano. Cinder cones rarely reach 300 meters in height but they have steep sides. Cinder cones grow rapidly, usually from a single eruption cycle (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDMtMDU.\">below<\/a>). Cinder cones are composed of small fragments of rock, such as pumice, piled on top of one another. The rock shoots up in the air and doesn\u2019t fall far from the vent. The exact composition of a cinder cone depends on the composition of the lava ejected from the volcano. Cinder cones usually have a crater at the summit.\n    <\/p>\n<div class=\"x-ck12-img-thumbnail x-ck12-nofloat\">\n      <!-- @@author=\"Courtesy of K Segerstrom\/US Geological Survey\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Paricutin_30_612.jpg\" --><!-- @@license=\"Public Domain\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223608\/201412291419878414581466_ce6ef40ffeb8aeaaca579432d40d5871-201412291419879768751411.jpg\" title=\"\" longdesc=\"In%201943%2C%20a%20Mexican%20farmer%20first%20witnessed%20a%20cinder%20cone%20erupting%20in%20his%20field.%20In%20a%20year%2C%20Paricut%26%23237%3Bn%20was%20336%20meters%20high.%20By%201952%2C%20it%20reached%20424%20meters%20and%20then%20stopped%20erupting.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDMtMDU.\" \/><\/p>\n<p>\n        In 1943, a Mexican farmer first witnessed a cinder cone erupting in his field. In a year, Paricut\u00edn was 336 meters high. By 1952, it reached 424 meters and then stopped erupting.\n      <\/p>\n<\/p><\/div>\n<p>\n      Cinder cones are often found near larger volcanoes (<strong>Figure<\/strong> <a href=\"#x-ck12-RVMtMDItMDEtMDYuanBn\">below<\/a>).\n    <\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Courtesy of NASA's Earth Observatory\" --><!-- @@url=\"http:\/\/earthobservatory.nasa.gov\/IOTD\/view.php?id=6585\" --><!-- @@license=\"Public Domain\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223609\/201412291419878414666914_1341117cfdfa4167528a7f3e16e7fcf4-201412291419879769414201.jpg\" title=\"\" longdesc=\"This%20Landsat%20image%20shows%20the%20topography%20of%20San%20Francisco%20Mountain%2C%20an%20extinct%20volcano%2C%20with%20many%20cinder%20cones%20near%20it%20in%20northern%20Arizona.%20Sunset%20crater%20is%20a%20cinder%20cone%20that%20erupted%20about%201%2C000%20years%20ago.%20\" alt=\"\" id=\"x-ck12-RVMtMDItMDEtMDYuanBn\" \/><\/p>\n<p>\n        This Landsat image shows the topography of San Francisco Mountain, an extinct volcano, with many cinder cones near it in northern Arizona. Sunset crater is a cinder cone that erupted about 1,000 years ago.\n      <\/p>\n<\/p><\/div>\n<h2>\n      Supervolcanoes<br \/>\n    <\/h2>\n<p>\n      <strong>Supervolcano<\/strong> eruptions are extremely rare in Earth history. It\u2019s a good thing because they are unimaginably large. A supervolcano must erupt more than 1,000 cubic km (240 cubic miles) of material, compared with 1.2 km<sup>3<\/sup> for Mount St. Helens or 25 km<sup>3<\/sup> for Mount Pinatubo, a large eruption in the Philippines in 1991. Not surprisingly, supervolcanoes are the most dangerous type of volcano.\n    <\/p>\n<p>\n      Supervolcanoes are a fairly new idea in volcanology. The exact cause of supervolcano eruptions is still debated. However, scientists think that a very large magma chamber erupts entirely in one catastrophic explosion. This creates a huge hole or <strong>caldera<\/strong> into which the surface collapses (<strong>Figure<\/strong> <a href=\"#x-ck12-RWFyU2NpLTA4MDMtMDY.\">below<\/a>).\n    <\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Courtesy of NASA\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Santorini_Landsat.jpg\" --><!-- @@license=\"Public Domain\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223610\/201412291419878414699012_1d05010df93693ce2f9981534a123e1a-201412291419879770063868.jpg\" title=\"\" longdesc=\"The%20caldera%20at%20Santorini%20in%20Greece%20is%20so%20large%20that%20it%20can%20only%20be%20seen%20by%20satellite.%20\" alt=\"\" id=\"x-ck12-RWFyU2NpLTA4MDMtMDY.\" \/><\/p>\n<p>\n        The caldera at Santorini in Greece is so large that it can only be seen by satellite.\n      <\/p>\n<\/p><\/div>\n<p>\n      The largest supervolcano in North America is beneath Yellowstone National Park in Wyoming. Yellowstone sits above a hotspot that has erupted catastrophically three times: 2.1 million, 1.3 million, and 640,000 years ago. Yellowstone has produced many smaller (but still enormous) eruptions more recently (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDgtMzEtWWVsbG93c3RvbmVfQ2FsZGVyYS5wbmc.\">below<\/a>). Fortunately, current activity at Yellowstone is limited to the region\u2019s famous geysers.\n    <\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"User:Kbh3rd\/Wikimedia Commons\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Yellowstone_Caldera.svg\" --><!-- @@license=\"Public Domain\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223611\/201412291419878414717977_21942f7c37cdf502f1b7c38b6ad16a3b-201412291419879770501395.png\" title=\"\" longdesc=\"The%20Yellowstone%20hotspot%20has%20produced%20enormous%20felsic%20eruptions.%20The%20Yellowstone%20caldera%20collapsed%20in%20the%20most%20recent%20super%20eruption.%20\" alt=\"\" id=\"x-ck12-SFMtRVMtMDgtMzEtWWVsbG93c3RvbmVfQ2FsZGVyYS5wbmc.\" \/><\/p>\n<p>\n        The Yellowstone hotspot has produced enormous felsic eruptions. The Yellowstone caldera collapsed in the most recent super eruption.\n      <\/p>\n<\/p><\/div>\n<p>\n      Long Valley Caldera, south of Mono Lake in California, is the second largest supervolcano in North America (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDgtMzItTG9uZy1WYWxsZXktQ2FsZGVyYQ..\">below<\/a>). Long Valley had an extremely hot and explosive rhyolite about 700,000 years ago. An earthquake swarm in 1980 alerted geologists to the possibility of a future eruption, but the quakes have since calmed down.\n    <\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\">\n      <!-- @@author=\"Image copyright Doug James, 2014\" --><!-- @@url=\"http:\/\/www.shutterstock.com\" --><!-- @@license=\"Used under license from Shutterstock.com\" --><\/p>\n<p>\n        <img decoding=\"async\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223614\/201412291419878414745420_94aa6363dd903997e88874ddf7089b3f-201412291419879771108680.jpg\" title=\"\" longdesc=\"The%20hot%20water%20that%20gives%20Hot%20Creek%2C%20California%2C%20its%20name%20is%20heated%20by%20hot%20rock%20below%20Long%20Valley%20Caldera.%20\" alt=\"\" id=\"x-ck12-SFMtRVMtMDgtMzItTG9uZy1WYWxsZXktQ2FsZGVyYQ..\" \/><\/p>\n<p>\n        The hot water that gives Hot Creek, California, its name is heated by hot rock below Long Valley Caldera.\n      <\/p>\n<\/p><\/div>\n<ul>\n<li>An interactive image of the geological features of Long Valley Caldera is available here:\n      <\/li>\n<\/ul>\n<p>\n      <a href=\"http:\/\/www.iris.edu\/hq\/files\/programs\/education_and_outreach\/aotm\/interactive\/B&amp;R_LongValleyCaldera.swf\">http:\/\/www.iris.edu\/hq\/files\/programs\/education_and_outreach\/aotm\/interactive\/B&amp;R_LongValleyCaldera.swf<\/a>\n    <\/p>\n<p>\n      A supervolcano could change life on Earth as we know it. Ash could block sunlight so much that photosynthesis would be reduced and global temperatures would plummet. Volcanic eruptions could have contributed to some of the mass extinctions in our planet\u2019s history. No one knows when the next super eruption will be.\n    <\/p>\n<p>\n      Interesting volcano videos are seen on National Geographic Videos, Environment Video, Natural Disasters, Earthquakes: <a href=\"http:\/\/video.nationalgeographic.com\/video\/player\/environment\/\">http:\/\/video.nationalgeographic.com\/video\/player\/environment\/<\/a>. One interesting one is \u201cMammoth Mountain,\u201d which explores Hot Creek and the volcanic area it is a part of in California.\n    <\/p>\n<h2>\n      Lesson Summary<br \/>\n    <\/h2>\n<ul>\n<li>Composite, shield, cinder cones, and supervolcanoes are the main types of volcanoes.\n      <\/li>\n<li>Composite volcanoes are tall, steep cones that produce explosive eruptions.\n      <\/li>\n<li>Shield volcanoes form very large, gently sloped mounds from effusive eruptions.\n      <\/li>\n<li>Cinder cones are the smallest volcanoes and result from accumulation of many small fragments of ejected material.\n      <\/li>\n<li>An explosive eruption may create a caldera, a large hole into which the mountain collapses.\n      <\/li>\n<li>Supervolcano eruptions are devastating but extremely rare in Earth history.\n      <\/li>\n<\/ul>\n<h2>\n      Review Questions<br \/>\n    <\/h2>\n<ol id=\"x-ck12-OGUzZWNmOWFkYjhmZmJkYTZhMTdiZThmNDk4OWMxNjg.-mqu\" class=\"x-ck12-decimal\">\n<li>Rank, in order, the four types of volcanoes from smallest to largest in diameter.\n      <\/li>\n<li>What factor best determines what type of volcano will form in a given area?\n      <\/li>\n<li>Which type of volcano is most common?\n      <\/li>\n<li>Why do pahoehoe and a\u2019a lava erupt from shield volcanoes? Why don&#8217;t they erupt from composite volcanoes?\n      <\/li>\n<li>Why are cinder cones short-lived?\n      <\/li>\n<li>If supervolcanoes are so big, why did it take so long for scientists to discover them?\n      <\/li>\n<\/ol>\n<h2>\n      Points to Consider<br \/>\n    <\/h2>\n<ul>\n<li>Composite volcanoes and volcanic cones usually have craters on the top. Why are the craters sometimes U- or horseshoe-shaped?\n      <\/li>\n<li>Think about plate boundaries again. What type of volcanoes do you think are found at convergent, divergent, and transform boundaries? How about at intraplate sites?\n      <\/li>\n<li>Some people have theorized that if a huge asteroid hits the Earth, the results would be catastrophic. How might an asteroid impact and a supervolcano eruption be similar?\n      <\/li>\n<\/ul>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-340\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Earth Science for High School. <strong>Provided by<\/strong>: CK-12. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/\">http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">CC BY-NC: Attribution-NonCommercial<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":277,"menu_order":5,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Earth Science for High School\",\"author\":\"\",\"organization\":\"CK-12\",\"url\":\"http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/\",\"project\":\"\",\"license\":\"cc-by-nc\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-340","chapter","type-chapter","status-publish","hentry"],"part":1286,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters\/340","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/users\/277"}],"version-history":[{"count":1,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters\/340\/revisions"}],"predecessor-version":[{"id":1159,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters\/340\/revisions\/1159"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/parts\/1286"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters\/340\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/media?parent=340"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapter-type?post=340"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/contributor?post=340"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/license?post=340"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}