Volcanic features Volcano

1 volcanic features

1.1 fissure vents
1.2 shield volcanoes
1.3 lava domes
1.4 cryptodomes
1.5 volcanic cones (cinder cones)
1.6 stratovolcanoes (composite volcanoes)
1.7 supervolcanoes
1.8 underwater volcanoes
1.9 subglacial volcanoes
1.10 mud volcanoes

volcanic features

lakagigar fissure vent in iceland, source of major world climate alteration of 1783–84



skjaldbreiður, shield volcano name means broad shield

the common perception of volcano of conical mountain, spewing lava , poisonous gases crater @ summit; however, describes 1 of many types of volcano. features of volcanoes more complicated , structure , behavior depends on number of factors. volcanoes have rugged peaks formed lava domes rather summit crater while others have landscape features such massive plateaus. vents issue volcanic material (including lava , ash) , gases (mainly steam , magmatic gases) can develop anywhere on landform , may give rise smaller cones such puʻu ʻŌʻō on flank of hawaii s kīlauea. other types of volcano include cryovolcanoes (or ice volcanoes), particularly on moons of jupiter, saturn, , neptune; , mud volcanoes, formations not associated known magmatic activity. active mud volcanoes tend involve temperatures lower of igneous volcanoes except when mud volcano vent of igneous volcano.

fissure vents

volcanic fissure vents flat, linear fractures through lava emerges.

shield volcanoes

shield volcanoes, named broad, shield-like profiles, formed eruption of low-viscosity lava can flow great distance vent. not explode catastrophically. since low-viscosity magma typically low in silica, shield volcanoes more common in oceanic continental settings. hawaiian volcanic chain series of shield cones, , common in iceland, well.

lava domes

lava domes built slow eruptions of highly viscous lava. formed within crater of previous volcanic eruption, in case of mount saint helens, can form independently, in case of lassen peak. stratovolcanoes, can produce violent, explosive eruptions, lava not flow far originating vent.

cryptodomes

cryptodomes formed when viscous lava forced upward causing surface bulge. 1980 eruption of mount st. helens example; lava beneath surface of mountain created upward bulge slid down north side of mountain.

volcanic cones (cinder cones)


izalco (volcano), located in cordillera de apaneca volcanic range complex in el salvador. few generations old, izalco youngest , best known cone volcano. izalco erupted continuously 1770 (when formed) 1958, earning nickname of lighthouse of pacific .

volcanic cones or cinder cones result eruptions of small pieces of scoria , pyroclastics (both resemble cinders, hence name of volcano type) build around vent. these can relatively short-lived eruptions produce cone-shaped hill perhaps 30 400 meters high. cinder cones erupt once. cinder cones may form flank vents on larger volcanoes, or occur on own. parícutin in mexico , sunset crater in arizona examples of cinder cones. in new mexico, caja del rio volcanic field of on 60 cinder cones.

based on satellite images suggested cinder cones might occur on other terrestrial bodies in solar system too; on surface of mars , moon.

stratovolcanoes (composite volcanoes)

cross-section through stratovolcano (vertical scale exaggerated):

stratovolcanoes or composite volcanoes tall conical mountains composed of lava flows , other ejecta in alternate layers, strata gives rise name. stratovolcanoes known composite volcanoes because created multiple structures during different kinds of eruptions. strato/composite volcanoes made of cinders, ash, , lava. cinders , ash pile on top of each other, lava flows on top of ash, cools , hardens, , process repeats. classic examples include mount fuji in japan, mayon volcano in philippines, , mount vesuvius , stromboli in italy.

throughout recorded history, ash produced explosive eruption of stratovolcanoes has posed greatest volcanic hazard civilizations. not stratovolcanoes have greater pressure build underlying lava flow shield volcanoes, fissure vents , monogenetic volcanic fields (volcanic cones) have more powerful eruptions, many times under extension. steeper shield volcanoes, slopes of 30–35° compared slopes of 5–10°, , loose tephra material dangerous lahars. large pieces of tephra called volcanic bombs. big bombs can measure more 4 feet(1.2 meters) across , weigh several tons.

supervolcanoes

a supervolcano has large caldera , can produce devastation on enormous, continental, scale. such volcanoes able severely cool global temperatures many years after eruption due huge volumes of sulfur , ash released atmosphere. dangerous type of volcano. examples include: yellowstone caldera in yellowstone national park , valles caldera in new mexico (both western united states); lake taupo in new zealand; lake toba in sumatra, indonesia; , ngorongoro crater in tanzania. because of enormous area may cover, supervolcanoes hard identify centuries after eruption. similarly, large igneous provinces considered supervolcanoes because of vast amount of basalt lava erupted (even though lava flow non-explosive).

underwater volcanoes

submarine volcanoes common features of ocean floor. in shallow water, active volcanoes disclose presence blasting steam , rocky debris high above ocean s surface. in ocean s deep, tremendous weight of water above prevents explosive release of steam , gases; however, can detected hydrophones , discoloration of water because of volcanic gases. pillow lava common eruptive product of submarine volcanoes , characterized thick sequences of discontinuous pillow-shaped masses form under water. large submarine eruptions may not disturb ocean surface due rapid cooling effect , increased buoyancy of water (as compared air) causes volcanic vents form steep pillars on ocean floor. hydrothermal vents common near these volcanoes, , support peculiar ecosystems based on dissolved minerals. on time, formations created submarine volcanoes may become large break ocean surface new islands or floating pumice rafts.

subglacial volcanoes

subglacial volcanoes develop underneath icecaps. made of flat lava flows @ top of extensive pillow lavas , palagonite. when icecap melts, lava on top collapses, leaving flat-topped mountain. these volcanoes called table mountains, tuyas, or (uncommonly) mobergs. examples of type of volcano can seen in iceland, however, there tuyas in british columbia. origin of term comes tuya butte, 1 of several tuyas in area of tuya river , tuya range in northern british columbia. tuya butte first such landform analyzed , name has entered geological literature kind of volcanic formation. tuya mountains provincial park established protect unusual landscape, lies north of tuya lake , south of jennings river near boundary yukon territory.

mud volcanoes

mud volcanoes or mud domes formations created geo-excreted liquids , gases, although there several processes may cause such activity. largest structures 10 kilometers in diameter , reach 700 meters high.