Physical State of the Earth

 They are three man layers of the earth.  1 Core  2 Mantle 3 Crust  .    Core: Core ia a ball like structure  which is present in the centre of earth it is divded in to two parts  1 )Inner core 2) Outer core      Inner core :  Inner core is hard and  solid . it is 1250 km thick and nearly  4300C° hot.                     Outer core : The outer core is in semi liquid  form. it is 2250km thick and about 3700C° hot.           Mantle :  it is the second layer of the earth. it is about 300Km  thick .the layer is composed of iron, silicon and magnesium  elements.Temperature  of  the  upper portion of the mantle is 870C° that reaches  up to 3600C° in the lower portion. Crust : it is the lightest and thinnest layer of the earth. it is mostly composed of  silicon and Aluminum element. On average it is 20  to 70 km  thick at continents while 5 to 10 km at ocean      Tectonic    plates   or plates  : The faults of the earth classified into a number  of separate pieces that are called tectonice plate or plates,    In the beginning all the countinents were joined  together   in a form  of whole mass that was  called pangaea.       Scientists  estimated from their observation  and research that plates can move with a  speed of 1cm to 10 cm  every year.      In  Sanfrancisco  (USA) a   severe  eaeth quick occurred in  1906. when American  plate moved forward  and rubbed  which Atlantic  plate.   Faults :   the crust of the earth is broken in different places. the  broken lines are called faults . Or a  faults is a fracture or zone  of fractures  between two blocks of rocks.      There are three  types of faults     1) Normal Fault    2) Reverse  Fault       3) lateral fault            Normal  Fault :   due  to tension, one side of a block  or fault  moves  upward while the other side either  remains on its place  or move  downward     Reverse  Fault:    Some time due to  tension from both sides,  one block  of fault  comes  or move on the other block.This is called reverse fault.     Lateral  Fault    : when two tectonic  plates Slide  along each other  in  opposite  direction  a fault is developed . This fault is called lateral  fault . it  can be very long.