VOLCANOES

VOLCANOES

     A volcano occurs where molten rock called magma erupts up from under Earth’s surface. An exploding volcano is one of the most incredible and dangerous sights on our planet. Volcanoes often form near the boundaries between tectonic plates,but they can also form elsewhere, at hot spots where hot rock moves upwards from deep inside Earth. There are about 550 active volcanoses on land, and more under the sea.







Lava

  Hot, molten rock that flows across the ground is called lava. It keeps this name even after it has cooled down and solidified into rock. Lava comes in different forms depending on what it is made of how stiff or runny it is, and how fast it flows.A’a lava-This is a thick lava flow made of basalt. Its surface is made up of loose, broken, and sharp chunks of lava that can tumble down the front of the lava flow as it moves.pahoehoe lava- This is basalt lava with an unbroken surface. As it surface skin is gradually stretched. The end result can end up looking either smooth or rope-like. Blocky lava- These chunks of lava form when stiff-flowing lava breaks up into angular blocks. These lava blocks hava smoother facesthan a’a lava.