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LITHOSHERE – I
VI. Distinguish between
Postition: Outer Layer,
Elements: Silica, Aluminium (SIAL)
Classification: Continental Crust, Oceamic Crust
Thickness: 30 km
Postition: Innermost Layer
Elements: Nickel, Iron (NIFE)
Classification: Inner core (Solid) Outer core (Liquid)
Thickness: 3480 km
• Epicentre is a point on the Earth's surface that lies directly above the focus.
• The impact of the Earthquake is felt the most at the epicentre.
• The point of origin of an Earthquake is called Hypocentre (Focus)
• It generates a series of elastic waves.
• In Divergent boundary the plates pull away from each other as magma pushes up from the mantle
• In convergent boundaries the plate moves toward each other and some times, a plate sinks under another.
• The waves pass through solids, liquids, and gases
• The velocity is 5.31 cm per second to 10.6 km per second
• 'P' waves are the fastest of all the Earthquake waves and the first to reach the epicentre.
• The waves travel only through solids.
• The velocity is 1 km per second to 8 km per second
• These transverse waves shake the ground perpendicular to the direction in which they propagate.
• Shield volcanoes are formed by intense viscous lava
• These are shallow depositions with gently sloping sides.
• Hence the lava flows out in all directions to create a shield.
E.g. Mauna Loa, Hawaii
• A lava dome or volcanic dome is roughly a circular mound formed due to the slow ejection of viscous lava from a volcano.
• As the lava is rich in silica with intense viscosity, it is prevented from flowing far from its vent. Eg. Paricutin, Mexico
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