Causes of Earthquake

 

Causes of Earthquakes

 

The cause of earthquakes may be broadly classified into following three categories.

 

1. Superficial

2. Volcanic Causes

3. Tectonic causes

 

1. Superficial Causes (Surface cause) : Earthquake of mild intensity which occur over the ground surface caused by dynamic agencies operating upon the surface of the earth are termed as Superficial once. The various causes are below:-

 

(a) A huge landslide or a rock fall along hill slopes.

(b) Giant sea waves and crashing beakers along sea shores.

(c) Running water, descending falls and cascades upon valley floor

(d) Heavy vibrating machinery in Industrial area.

(e) movement of locomotives and other heavy vehicles on the earth surface.

(f) Man made explosions and other nuclear tests.

(g) Mining blasts in mining areas.

 

2. Volcanic causes : volcanic activities taking place in different parts of the world, oftenly volcanic outbursts or explosions during which the surface of the earth trembles. The impact thus generated is sometimes so strong that it causes earthquake or seismic shocks in the nearby areas.

 

3. Tectonic causes : Tectonic causes are those which originate within the earth's crust and are necessarily associated with the relative movements of rock masses forming the crust of earth. Tectonic earthquake occur due to. :

 

(a) Displacement or rupturing of rock masses along preexisting cracks or faults.

(b) Development of new fault planes.