EARTHQUAKES

EARTHQUAKES

EARTHQUAKES

Earth Quake

An earthquake is the sudden vibration of the earth’s surface by rapid release of energy. This energy is released when two parts of rock masses move suddenly in relation to each other along a fault.

Causes of EarthquakeDepending upon their mode of origin, the earthquakes are classified into following groups.

i. Earthquake Due to Surface CausesEarthquake may be generated by landslips and collapse of the roof of underground caverns; most of these are very minor

ii. Earthquake Due to Volcanic CausesVolcanic eruptions may also produce earthquakes but such earthquakes are generally very feeble.

iii. Earthquake Due to Tectonic CausesTectonic earthquakes are the most numerous and unusually the most disastrous. They are caused by shocks with originate in the earth’s crust due to sudden movement along faults.
One the basic of the depth the focus, the earthquakes are divided into the following groups.

iv. Shallow Focus EarthquakesEarthquakes having depth of focus upto 55 km.

v. Intermediate Focus EarthquakesEarthquake having depth of focus 55-300km.

vi. Deep Focus EarthquakesEarthquake having depth of focus 300-650km

Effects of Earthquake

v Buildings are damaged and people get frightened.
v Roads are fissured, railway lines are twisted and brides are destroyed.
v In cities, ground waves disrupt underground services and start fires.
v Rivers change their courses; Fissures are opened up in the ground which may cause spring.
v Permanent tilting of the land mass may occur in certain areas. Landslides may occur in hilly regions.