GEOLOGY

Detailed explanation-1: -Earthquakes occur when energy stored in elastically strained rocks is suddenly released. This release of energy causes intense ground shaking in the area near the source of the earthquake and sends waves of elastic energy, called seismic waves, throughout the Earth.

Detailed explanation-2: -Earthquakes are the result of sudden movement along faults within the Earth. The movement releases stored-up ‘elastic strain’ energy in the form of seismic waves, which propagate through the Earth and cause the ground surface to shake.

Detailed explanation-3: -This gradual accumulation and release of stress and strain is now referred to as the “elastic rebound theory” of earthquakes. Most earthquakes are the result of the sudden elastic rebound of previously stored energy.

Detailed explanation-4: -Rocks have three possible responses to increasing stress (illustrated in figure 3): elastic deformation: the rock returns to its original shape when the stress is removed. plastic deformation: the rock does not return to its original shape when the stress is removed. fracture: the rock breaks.

Detailed explanation-5: -The earthquake relieves the stress, the fault is stuck again, and the cycle of stress buildup and release begins anew. This process has been documented on the Hayward fault and San Andreas fault for the past few thousand years using geologic investigations.