Answer in brief

What are the effects of earthquakes on the earth’s surface and human life?

An earthquake occurs when the tension in the normal movements within the earth’s crust increases leading to formation of massive waves creating trembling on the earth’s surface. Earthquakes are naturally devastating in nature and have both primary and secondary effects. The primary effects are mostly observed on the earth’s surface, while secondary effects are observed on human life.

Primary effects –

• The passage of seismic waves through the ground, causes it to shake which can be gentle or extremely violent depending on the magnitude of the earthquake. This leads to rupturing on the surface and/ or creation of faults further weaking the ground stability.

• Landslides are caused by earthquakes both by direct rupture and by sustained shaking of unstable slopes. They can easily destroy buildings in their path, or block roads and railroad lines, or take hilltop homes with them as they tumble.

• Earthquakes can cause tsunamis or seismic sea waves which is caused by the displacement of a large volume of water, generally in an ocean or a large lake because of ground shaking and displacement.

• In a similar fashion, earthquakes can also change the existing groundwater level in an area in which it occurs.

• In mountain areas, earthquakes can also cause the accumulated snow on mountain tops to dislodge through the shaking and create an avalanche.

Secondary effects –

• Earthquakes can cause devastating fires which in turn affect human life and property.

• Human life and property are also lost and damaged due to building collapse in the event of an earthquake.

• Since earthquakes tend to damage the earth’s surface, transportation routes like roads and railways are also severely affected and often destroyed during earthquakes of higher magnitudes.

• The same reason applies for communication systems.