Friday, September 3, 2010

Natural Disasters-Volcanoes and Earthquakes





Volcanic eruptions and earthquakes are both natural disasters depending on where they are situated. They both occur deep inside the earth's crust which then affects the earth's surface, where we live. The more human population living in the area    the bigger the disaster.


Volcanic Eruption
Volcanic Eruptions


A volcano is a mountain where magma erupts though surface of the planet. The ‘crashing’ of tectonic plates at the plate boundaries causes this eruption. It is estimated that one in ten of the   world's population live in the ‘danger range’ of a volcano. There are 1511 ‘active’ volcanoes across the globe and many more dormant ones that could recharge at any moment.


Earthquakes

Earthquake
 Earthquakes are caused by the motion of tectonic plates—individual sections that make up the Earth's surface, like panels on a football. An earthquake is the shaking of the ground when there is a sudden breaking and shifting of these large plates. Earthquakes are amongst the most powerful natural disasters and can cause further disasters such as tsunamis and landslides. Earthquakes are measured by a seismometer which records the size of the seismic waves.