Volcanoes vs Earthquakes
Volcanoes and earthquakes are natural hazards that have great destructive potential and have been a source of enormous loss of property and innocent lives since time immemorial. While students are told about both these natural causes of disasters, there are many who cannot differentiate between a volcano and an earthquake. This article will try to make the picture clearer by highlighting the features of both types of natural hazards.
In the simplest of terms, a volcano can be thought of as a mountain with an opening that goes downward below the surface of the earth. Deep below the surface, earth is extremely hot. This heat melts some of the rocks which become a thick flowing substance called magma. This magma, being lighter than surrounding rocks rises up through the opening and gets collected in magma chambers that are a part of the mountain visible to all. Sometimes, this magma comes out of the structure through fissures and cracks, and this is when we say that the volcano has erupted. The hot, flowing liquid that comes out from the volcano is called lava which is nothing but magma that is formed inside the volcano.
The lava, when it is thin and fast moving, causes more destruction than when it is thick and slow moving. More gases erupt out of thin lava than when it is thick. Destruction caused by lava is enormous, but it rarely kills people as people can get away from the site in time easily. It is when explosions accompany volcanic eruptions that they become more dangerous because of the presence of deadly ash that can suffocate plants, animals and human beings. Mudflows from volcanoes have sometimes buried entire villages and cities existing around them.
Volcanoes remain silent for thousands of years and then suddenly become active which is why people around them are not aware of the dangers.
Earth is not a uniformly solid sphere from inside and there are many faults along the planes inside the earth. During its rotation and revolution, rocks break and slip along faults. This movement of rocks along a fault releases enormous amount of energy in the form of seismic waves that have the potential to shake the ground violently. This shaking and tremor causes buildings to collapse, resulting in heavy loss of property and innocent lives.
As described above, the structure underneath the surface of earth is made up of tectonic plates that keep sliding and striking against each other. This causes release of energy that violently shakes up ground. Shaking of ground causes untold damage above the epicenter of this earthquake and this shaking or tremor decrease in amplitude and magnitude with increasing distance from the epicenter of the earthquake.
Contrary to common misconception because of some Hollywood movies, there is no tearing up of ground though there may be some cracks that show up on the surface. It is just the tremor that causes all the destruction. The earth has been divided into seismic zones based upon their seismicity or the frequency with which they have experienced tremors in the past.
Difference Between Volcanoes and Earthquakes
• There is no ostensible relation between earthquakes and volcanoes though there are zones on earth where both natural hazards are found together.
• Volcanoes result from openings in the surface of the earth that brings along hot magma (molten rocks) with its wake that erupts from fissures and cracks in the mountain that is referred to as a volcano.
• Earthquakes are a result of the tremor that is felt on the ground because of release of energy that is accompanied with breaking of rocks. The surface of the earth is not uniform inside and there is constant movement of tectonic plates inside. These plates collide with each other, resulting in violent shaking of earth that causes huge loss of property and innocent lives.