The volcanoes and the safety precautions must be taken at the occurrence of the volcanoes .
The volcano is an opening in the Earth’s crust which permits the passage of the trapped gases and the molten materials ( lava ) .
The causes of the volcano occurrence :
|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 :
- The volcanic vent : It is an opening lies at the top of the volcano .
- The volcanic pipe ( or neck ) which is a cylindrical cavity that connects the Earth’s interior with the surface , through which the magma moves during its ascendence .
- Volcano cone which is the body of the volcano . It consists of molten materials after their solidification and accumulation around the volcanic vent .
The products of volcano :
The materials ejected during the volcanic eruption are fragmented materials , The lava and the volcanic gases .
The fragmented materials which are materials that the volcano emanates . These materials are different in size ranging from big projectiles to the volcanic ashes .
Lava ( or lava flows ) which are molten materials mass that spreads on the volcanic sides .
The volcanic gases which are the fused ( mixed ) gases with the magma and the most important of them are water vapour and oxides of carbon , nitrogen and sulphur .
Harms of volcanoes :
The Lava and the lava flows cover and destruct whole towns and villages .
Spreading of the poisonous gases and the volcanic dusts into far places and they cover large areas .
The fire catches in the forests and neighbouring places to the volcano and causes a lot of damage .
The volcanoes destroy the cultivated lands near it .
The benefits of volcanoes :
In some countries , the thermal energy resulted from the volcano is used to produce the electricity .
- The volcanic projectiles and ashes form more fertile soil , So , the most important crops are produced .
- They form new islands in the seas , and increase the area of lands .
- 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 the people from the neighbouring areas of the volcano as soon as possible .
To avoid the poisonous gases emanated from the volcanoes , The people must take account of the instructions of the forecasting of the wind direction .