Earthquakes and volcanoes
- 2. EARTHQUAKE- An earthquake is a motion of the ground surface, ranging from a faint tremor to a wild motion capable of shaking buildings. OR EARTHQUAKE-An earthquake are vibration of earth caused by ruptures and sudden movements of rocks that have been strained beyond their elastic limit. In Himalyan state(or different state) so what are various disaster it is prone to and what are the steps taken by you?
- 3. Lines of equal seismic intensity. Shallow Intermediate Deep Large Earthquakes Depth α 1 / Intensity RICHETER SCALE: Access the magnitude max(8.8) to min(2.0) MERCALLI SCALE: Intensity
- 4. A volcano is a vent (opening), through which heated materials consisting of gases, water , liquid lava, ash & fragment of rocks are ejected from the highly heated interior to the surface of earth. VULCANICITY PROCESSES MOLTEN ROCK MATERIAL Magma rises into the crust or is poured out on its surface, there to solidify as a crystalline or semi- crystalline rock. VULCANISM – Includes all phenomenon connected with the movement of heated materials from the interior towards the surface of the earth.
- 5. Where does water vapour and gases in a volcano come from? A A B BSubjugate Below When this subjugation took place under water also went which evaporation due to high temperature as a result various gases and vapour comes out. CAUSES OF VOLCANO Sea floor spreading. Plate tectonic. Mountain building process Subducted mountains Ridges Origin of magma at subduction zone.
- 6. HAWAIIAN ERUPTION Extremely fluid basic lava flow Shield volcano Explosion is rare STROMBOLIAN ERUPTION Less fluid lava + fragmented material Explosion are common (North sicily Italy) VULCANIAN ERUPTION High viscosity Violent explosion Darts cauliflower like clouds PELEAN ERUPTION Glowing cloud (Mt. Petee West Indies) PLINIAN ERUPTION Greater violence Cloud in shape of Pine tree
- 7. BASALT CONES Low (fluid) height e.g. Rangitoto BASALT DOMES Shields e.g. Hawaiian ASH OR CINDER CONE Explosive eruptions with pyroclastic material Height 100m(max) COMPOSITE OR STRATO CONE • Alternating sheets of lava and pyroclastic material. • e.g. Fujiyama (Japan), Vesuvious (Italy). 1. Active volcanoes 2. Dormant volcanoes 3. Extinct volcanoes Stromboli volcanoes • Stromboli Light house of mediterranian sea
- 8. 1. VOLCANIC CRATERS Funnel shaped basin surrounding the vent. 2. COLDERAS • Very large craters a . Repeated explosion b. Coalescence of several small crater c . Collapse e.g. Yellowstone 3. ASH SHOWERS 4. VOLCANIC MUD FLOWS • Heavy rain and nuee ardented deposits. • Mingling of nuee ardentes with water bodies 5. PLUG DOMES Plug • Viscous lava don’t spread but form cylindrical plugs in the crater of a volcano
- 9. 6. SALFOTORAS • Late phase of volcanic activity prior to the extinction of volcanic cone. • Gentle emission of sulfurous gases and stream without violent explosion. 7. GEYSERS It is a violent ejection of steam and superheated water from an underground source through a hole in the ground 8. Hot springs` NOTE: They are not only formed due to volcanic activity.