How Plates Move As a result of the Geologist's researcher in the 1960's that the Earth's hard outer layer is not a just one piece. It is included 12 large pieces of plates. On the map, the red lines show them. 1. Convergent boundaries; tow plates strike zone forming a   subduction zone and mountains 2. Divergent  boundary ;  tow  plates separating zone as  in  a  mid-ocean  ridges  that  move in opposed directions. 3. Transform boundary; tow plates' boundary such as in Darooneh Fault of Iran that is slipping past each other. This is such as a tear in the Earth's crust. They move very slowly on the surface of the Earth as though on a conveyor  belting .In the past year, the convection  currents  in  the  much  hotter  mantle  move  the  plates about1/2 to 4 inches. Lava is very hot molten material and when two plates move or strike, they causes the lava escape from the mantle. Mountain, deep underwater valleys called trenches and volcanic activity are caused by plates collisions. As mountains and valleys are formed, natural disaster like earthquake and volcanic activity can happen and can affect on humans for many years . Where two plates are diverging, the Earth is producing new  crust. This happens in the middle parts of great oceans .In the world, this mid ocean ridges are the longest constantly running mountain range .These ridges are about 40,000 miles long and connected!! For example the mid Atlantic ridge, is one of these mid – oceanic ridges that is spreading apart and making the Atlantic ocean wider. When two part of oceanic Plates diverge, the mantle Melt and  magma descend and make newly formed oceanic rocks. The bottom of the Atlantic ocean is filled with some of the youngest crust of Earth. For example, in the North Atlantic Iceland is still being formed at this Mid - Atlantic ridge. It is getting larger as the western Hemisphere moves away from Europe and Asia. On the other hand, pacific ocean is becoming smaller. It is due to westward movement of South  American and  North  American plates toward Australia  and  Asia . They are crashing into denser and  thinner oceanic plates of the Pacific. The movement of the oceanic plates deep into the mantle, destroying the oceanic plates is called "Subduction Zone", the boundary in which on oceanic plate is driven  down ands destroyed by a continental plate . The Pacific Ocean area has more geological activity and earthquakes than any other area of the world. This area is nicknamed "Fire Ring" because of all the spread volcanoes.  They form magma as the mantle rocks melt. The magma will rise because is less dense than the surrounding mantle material. Pressure in the magma cracks cause the pressure on the rocks and overlying rocks to decrease. Then magma enters into the crack .The repetition of this process bring the magma towards the surface. This process repeat thousands of times. If the magma reaches the surface, a volcano will form. Lava is created when magma does reach the surface. In the following lessons you will learn more about volcanoes. When the volcano explores, a peak-like mountain has built. The lava build the mountain higher with each explosion, when ash and other pyroclastic material will continue.  Tow model were formed in this way are the Oromie-Dokhtar mountain range in the west north-south east Iran and  the Andes mountains in South America.   This is a cross section of the Earth in the Southern Hemisphere. The map shows a subduction zone that has created the Peru-Chile Trench at the western edge of South America. This subduction zone has produced the Andes Mountains which run along the entire west coast of South America. It also shows you the Mid-Atlantic Ridge which is spreading the Atlantic Ocean making it wider and wider. The cross section shows two processes at work; 1. "Old Crust" being destroyed at a subduction zone and 2. "New Crust" being produced at the Mid-Atlantic Ridge The pink lines on this map of the Pacific Ocean represent deep ocean trenches. These trenches are some of the lowest points on the crust of the Earth. Marianas Trench north of New Guinea is the deepest point on the Earth's surface at 36,201 feet below sea level. Marianas Trench is 7,173 feet deeper than Mount Everest is high!!!! Trenches surround almost all of the Pacific Ocean. Some of the other trenches of the Pacific are the Aleutian, Peru-Chile, Kuril, and the Japan trench. There are trenches wherever continental plates and oceanic plates collide. The Java Trench in the Indian Ocean is the deepest point of that ocean at 24,442 feet below sea level.