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Saturday, May 31, 2014

The volcanoes and the safety precautions must be taken at the occurrence of the volcanoes .



Volcanoes eruption damage towns and villages .
Lava ( lava flows ) are molten materials mass that spreads on the volcanic sides .

There are thousands of volcanoes on the Earth's surface . But sixty one only of them are active as an evidence of the permanent activities and movement beneath the Earth's crust . 

You should know that Volcano is an opening in the Earth's crust which permits the passage of the trapped gases and the molten materials ( lava )  .

 

Causes of the volcano occurrence :

Volcanoes have more dangerous destructive effects .
 lava flows cover and destruct whole towns and villages .

The direct cause of the volcano occurrence is the presence of weak parts in the Earth's crust , where molten materials are going out to the Earth's surface .

 

Parts of volcano :

 

It consists of three parts which are : 

 

  1. The volcanic vent : It  is an opening lies at the top of the volcano .

     

  2. Volcanic pipe ( or neck ) which is a cylindrical cavity that connects the Earth's interior with the surface , through which magma moves during its ascendence .

     

  3. Volcano cone which is the body of the volcano . It consists of molten materials after their solidification and accumulation around the volcanic vent . 

     

Products of volcano :

 


The materials ejected during the volcanic eruption are fragmented materials , lava and the volcanic gases .

 

  1. Fragmented materials which are materials that the volcano emanates . These materials are different in size ranging from big projectiles to volcanic ashes .

     

  2. Lava ( or lava flows )  which are molten materials mass that spreads on the volcanic sides .

     

  3. The volcanic gases which are the fused ( mixed ) gases with magma and the most important of them are water vapour and oxides of carbon , nitrogen and sulphur . 

     

Harms of volcanoes :

 

  1. Lava and lava flows cover and destruct whole towns and villages .

     

  2. Spreading of the poisonous gases and volcanic dusts  into far places and they cover large areas .

     

  3. Fire catches in the forests and neighbouring places to the volcano and causes a lot of damage .

     

  4. The volcanoes destroy the cultivated lands near it .

     
    Parts of volcano are volcanic vent , volcanic pipe and volcanic cone .
    Volcanoes form new islands in the seas , and they increase the area of lands .

Benefits of volcanoes : 

 

  1. In some countries , the thermal energy resulted from volcano is used to produce electricity .

     

  2. The volcanic projectiles and ashes form more fertile soil , So  the most important crops are produced  .

     

  3. They form new islands in the seas , and increase the area of lands .

     

  4. The volcanic rocks  are produced by the volcanoes , and they have great economic values . 

     

Safety and security precautions that must be taken at the occurrence of volcanoes :

 

  • During the volcanoes , we must evaluate people from the neighbouring areas of the volcano  as soon as possible .

     

  • To avoid poisonous gases emanated  from the volcanoes , People must take  account of the instructions of the forecasting of  the wind direction  .   

 

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