Classification of volcanoes On basis of On basis of periodicity On basis of intensity composition/structure Cinder and ash cone Basic cone e Hawaiin type . Strombolian . Vulcanian . Peleen . Visuvius . Active-Mt Etna Dormant-Mt fujiyama Extinct- Narcondam . Acid cone . Composite Parasite
Composite Cones Composite Cone volcanoes are steep-sided . made of alternate layers of ash and lava. Often the lava cools to create a plug in the vent, meaning that a huge explosion is needed to remove it. . The best example is Mt. St. Helens. Subsiduary Cone Volcano made of alternating layers of ash and lava Steep sided
Cinder cones Cinder cones are simple volcanoes which have a bowl-shaped crater at the summit and only grow to about a thousand feet, the size of a hill They usually are created of eruptions from a single opening, unlike a strato-volcano or shield volcano which can erupt from many different openings. . Cinder cones are simple volcanoes which have
Acid cones Acid cone volcanoes are steep sided due to the fact that the lava is thick and acidic, meaning that it doesn't flow far before solidifying, for example Mt. Pelee. Plug forms in the vent Steep sided due to thick, slow moving lava Convex sides Lava
Shield cone . Shield cone volcanoes are wide-based, with gentle slopes. Their lava is runny and thin, which means that it can travel a long way before cooling and solidifying. Often these eruptions are non-violent and can last for years, such as the one at Kilaueain Hawaii. . Cross-Section of a Shield Volcano Thin (1-10 m thick) basalt lava flows Slope 5-10p Basaltic Magma Chamber
Geysers, Fumaroles and Hot Springs .A fumarole is vent where gases, either from a magma body at depth, or steam from heated groundwater, emerges at the surface of the Earth Hot springs or thermal springs are areas where hot water comes to the surface of the Earth .Cool groundwater moves downward and is heated by a body of magma or hot rock. Minerals dissolved in the high temperature water are often precipitated when the water cools at the surface.
Volcanic landforms Volcanic cones . Craters, caldera . Lava domes, plains Extrusive . Batholith . Laccolith Phacolith Lopolith Sill, dykes . Volcanic plugs Intrusive
Intrusive landforms Intrusion of Magma in sedimentary rocks Sills (Horizontal) Dyke (Vertical) Laccolith - magma which could not come out Lopolith - saucer-shaped Phacolith - shape like waves Batholith - intrusive granitic rock
Volcano Lava flows & Pyroclastic deposits Volcanic neck Dike Sill Sill Laccolith Stock Dike Dike Batholith
PREDICTING ERUPTIONS: VOLCANO MONITORING Predict Eruptions by Study and comparison of past eruptions Warning Signs- Small quakes (seismicity) remote sensing hydrology Swelling of slopes as Changes in water pH seismicity Changes in gases emitted ground deformation geophysical mcasureme
B Tech from MNIT, Jaipur. Appeared in CSE interview thrice. Loves teaching and playing badminton.