Volcanoes Deepa&Kirti


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Volcanoes Deepa&Kirti

  1. 1. Deepa S Beli Keerti Yadav VOLCANOES
  3. 3. HISTORY <ul><li>On Aug 24, A.D. 79, Vesuvius volcano suddenly exploded in Roman cities. </li></ul><ul><li>After that 100 of yrs it was considered as “Extinct”. </li></ul><ul><li>Then the word ‘Volcano’ originates from “Vulcan” – God of fire in Roman mythology . </li></ul>
  4. 4. NATURE <ul><li>conical hill or mountain built around the vent. </li></ul><ul><li>The term volcano also refers to opening. </li></ul><ul><li>Built by accumulation of their own eruptive product lava,bomb,flows & tephra. </li></ul>
  5. 5. MEANING <ul><li>“ When pressure from the molten rock beneath the earth’s surface becomes too great the rock usually accompanied by lava or gases, escapes through a fissure or vent in crust of earth”. </li></ul>
  6. 6. COMPOSITION <ul><li>Volcano mainly consists of molten rock and </li></ul><ul><li>other liquids. </li></ul><ul><li>a) Liquid composed of O, Si, Al, Fe, Mg, Na, </li></ul><ul><li> Ca, Mn, K. </li></ul><ul><li>b) Magma-molten rock below the earth’s </li></ul><ul><li>surface. </li></ul><ul><li>c) Lava-fluid erupted from volcanic vent. </li></ul><ul><li> </li></ul><ul><li> </li></ul>
  7. 7.   Fountaining lava and volcanic debris during the 1959 Kilauea Iki eruption of Kilauea Volcano, Hawaii.
  8. 8. TYPES OF VOLCANOES <ul><li>Cinder Volcano </li></ul><ul><li>Composite Volcano </li></ul><ul><li>Shield Volcano </li></ul><ul><li>Lava Domes </li></ul>
  9. 9. CINDER VOLCANOES <ul><li>Simplest </li></ul><ul><li>Built from particle & blobs of congealed lava. </li></ul><ul><li>Lava solidifies & fall from single vent. </li></ul><ul><li>Numerous in West North America . </li></ul> 
  10. 11.     Parícutin Volcano, Mexico, is a cinder cone rising approximately 1,200 feet above the surrounding plain.
  11. 12. COMPOSITE VOLCANOES <ul><li>Steep sided, symmetrical cones. </li></ul><ul><li>Built from layer of lava flow, ash, cinder. </li></ul><ul><li>Rises up to 8000 ft from base. </li></ul><ul><li>Conspicuous volcano in </li></ul><ul><li>a] Mt.Fuiji, Japan. </li></ul><ul><li>b] Mt.Shasta, California . </li></ul>
  12. 14.     Shishaldin Volcano, an imposing composite cone, towers 9,372 feet above sea level in the Aleutian Islands, Alaska.
  13. 15. SHIELD VOLCANOES <ul><li>Slow process volcano </li></ul><ul><li>Built from fluid lava. </li></ul><ul><li>Flows in all direction from central vent like warrior’s shield. </li></ul><ul><li>Linear chains in Hawaiian Island. </li></ul><ul><li>a) Kilauea </li></ul><ul><li>b) Mauna Loa </li></ul>
  14. 17.     Mauna Loa Volcano, Hawaii, a giant among the active volcanoes of the world; snow-capped Mauna Kea Volcano in the distance.
  15. 18. LAVA DOMES <ul><li>Built from small bulbous masses of lava. </li></ul><ul><li>Viscous to flow any great distance. </li></ul><ul><li>Piles over & around the vent. </li></ul><ul><li>Expansion makes outer surface cool & harder. </li></ul><ul><li>Eruption of Katmai volcano in Alaska in 1912 </li></ul>
  16. 20. The Novarupta Dome formed during the 1912 eruption of Katma Volcano, Alaska.
  17. 21. VOLCANIC ERUPTION <ul><li> During an episode of activity, a volcano commonly displays a distinctive pattern of behavior. </li></ul>
  18. 22. TYPES OF ERUPTIONS <ul><li>Eruption is often labeled with the name of well known volcanoes, where characteristic behavior are similar . </li></ul><ul><li>Strombolian eruption </li></ul><ul><li>Volcanian eruption </li></ul><ul><li>Vesuvian eruption </li></ul><ul><li>Pelean eruption </li></ul><ul><li>Hawaiian eruption </li></ul>
  19. 23. STROMBOLIAN ERUPTION <ul><li>Observed in 1965, during activity of Irazua volcano in Costa Rica. </li></ul><ul><li>Huge clots of molten lava from ejected from summit crater. </li></ul><ul><li>Forms luminous arcs through the sky. </li></ul><ul><li>From the flanks of the cone, lava clots combined to stream down the slope in fiery rivulets. </li></ul>
  20. 24.   Irazua volcano in Cost Rica,1965.
  21. 25. VULCANIAN ERUPTION <ul><li>Observed at Paricutin volcano in Mexico, 1947. </li></ul><ul><li>Explodes dense cloud of ash-laden gas from the crater. </li></ul><ul><li>Rises very high & forms whitish clouds near the cone. </li></ul>
  22. 26.   Parícutin Volcano, Mexico, 1947. 
  23. 27. VESUVIAN ERUPTION <ul><li>Explodes great quantities of ash-gas laden </li></ul><ul><li>Forms cauliflower shaped clouds high above the volcano. </li></ul><ul><li>Observed at Mt.Vesuvius in Italy in A.D. 79. </li></ul>
  24. 28.     Mount Vesuvius Volcano, Italy, 1944.
  25. 29. HAWAIIAN ERUPTION <ul><li>Observed in Hawaii of Mauna Loa in 1950. </li></ul><ul><li>Molten incandescent lava spurts from a fissure on the volcanoes left zone. </li></ul><ul><li>Lava may collect in old pit crater to form lava lakes. </li></ul>
  26. 30.     Mauna Loa Volcano, Hawaii, 1950.
  27. 31. PELEAN(GLOWING CLOUD) ERUPTION <ul><li>Observed in Mayon volcano in Philippines in 1968. </li></ul><ul><li>Large quantity of gas, dust, ash & incandescent lava. </li></ul><ul><li>Lava moved down slope at velocity of 100 miles per hour which look like tongue shaped. </li></ul>
  28. 32. <ul><li>The most powerful eruptions are called &quot;plinian&quot; and involve the explosive ejection of relatively viscous lava. </li></ul><ul><li> </li></ul>
  29. 33.     Mount St. Helens about noon, May 18, 1980 .
  30. 34. SUBMARINE VOLCANOES <ul><li>Submarine volcano & volcanic vents are common features on zones of ocean floor. </li></ul><ul><li>Disclose their presence by blasting steam & rock debris high above the surface of the sea. </li></ul><ul><li>With great depth & tremendous depth of water volcano, confines the pressure, prevents the formation of steam & gases . </li></ul>
  31. 35.  
  32. 36.     Submarine eruption of Myojin-sho Volcano, Izu Islands, Japan, on September 23, 1952.
  33. 37. EXTRATERRESTRIAL VOLCANISM <ul><li>Planetary exploration is began in 1960’s with it’s product on Mars,Moon &Venus. </li></ul><ul><li>Pounds of volcanic rock collected during various Apollo lunar landing mission. </li></ul><ul><li>From 1976 – 79 Viking mission studied the volcanoes on Mars i.e. about Olympus Mons volcano. </li></ul>
  34. 38.    
  35. 39. MONITORING & RESEARCH <ul><li>Began in 1912 , by Thomas A. Jaggar. </li></ul><ul><li>Founded Hawaiian volcano observatory (HVO) on rim of Kilauea’s Caldera. </li></ul><ul><li>Monitoring of Seismic activity preceding. </li></ul><ul><li>Records & analysis an volcanic phenomenon which includes ground moments earthquakes . </li></ul>
  36. 40. VOLCANO & PEOPLE <ul><li>Volcanic materials breaks down to form some fertile soils on earth. </li></ul><ul><li>People use volcanic products as construction materials. </li></ul><ul><li>As abrasive & cleaning agents. </li></ul><ul><li>Raw materials for many chemical & industrial uses. </li></ul><ul><li>Internal heat of some volcanic system has been harnessed to produce geothermal energy. </li></ul>
  37. 41. CONCLUSION