Earthquake in india : How earthquake is dangerous ?

Earthquakes are natural phenomena caused by the sudden release of energy in the Earth's crust, resulting in seismic waves. This release of energy is typically caused by the movement of tectonic plates beneath the Earth's surface. When these plates grind against each other or collide, stress builds up until it's released in the form of an earthquake. 

The point within the Earth where the earthquake originates is called the hypocenter, and directly above it on the Earth's surface is the epicenter. Earthquakes can vary in size from those that are so weak that they cannot be felt to those violent enough to toss people around and destroy whole cities.

Seismometers are instruments used to measure and record the intensity of seismic waves generated by earthquakes. The magnitude of an earthquake is a numerical scale that quantifies the amount of energy released. The Richter scale and the moment magnitude scale are commonly used to measure earthquake magnitude.

Earthquakes can have devastating effects, including ground shaking, surface rupture, landslides, tsunamis, and liquefaction. Scientists and engineers study earthquakes to better understand their causes and effects, which helps in creating strategies to minimize their impact on human societies.