EARTHQUAKES

PRERNA FOR IAS

EARTHQUAKES

1. Meaning of Earthquakes

An earthquake is the sudden shaking or vibration of the Earth’s surface caused by the release of energy within the Earth’s crust. This energy is generated when rocks break or slip along faults due to the movement of tectonic plates. Earthquakes can occur anywhere but are most common near plate boundaries. The intensity of earthquakes varies from minor tremors that are barely felt to powerful events that can cause widespread destruction. Earthquakes are natural hazards that affect human life, infrastructure, and the environment. Understanding their causes and effects is important for disaster preparedness and risk reduction.

2. Causes of Earthquakes

Earthquakes are mainly caused by the movement of tectonic plates beneath the Earth’s surface. As these plates move, stress gradually accumulates in rocks along fault lines. When the stress exceeds the strength of the rocks, they suddenly break or slip, releasing large amounts of energy. This energy travels through the Earth as seismic waves, causing the ground to shake. Earthquakes may also result from volcanic activity, landslides, mining operations, and reservoir-induced pressure. However, tectonic activity remains the most common cause. The study of earthquake causes helps scientists identify earthquake-prone regions and improve safety measures.

3. Focus and Epicenter

The focus, also called the hypocenter, is the point inside the Earth where an earthquake originates. It is the location where rocks first break and release energy. The epicenter is the point on the Earth’s surface directly above the focus. Earthquake effects are usually strongest near the epicenter because it is closest to the source of the released energy. Scientists use seismic instruments to determine the location of the focus and epicenter. Identifying these points is essential for understanding earthquake patterns, assessing damage, and planning disaster response. They are key concepts in earthquake studies and seismology.

4. Seismic Waves