An earthquake is the intense shaking of the earth's surface caused by movements in the earth's outermost layer. The earth has four primary layers: a solid crust, a hot, nearly solid mantle, a liquid outer core, and a solid inner core. The solid crust and the stiff layer of the mantle that makes up the Lithosphere, which is the rigid, rocky outer layer of the Earth made up of plates called tectonic plates  are constantly shifting as they drift around on the viscous or slowly flowing. This continuous movement causes stress on earth's crust.

When the stress is too intense, it leads to cracks in the earth called faults, which the movement of the earth's crust at the fault line causes earthquakes. The causes might be natural forces where sudden energy is released by elastic strain, gravity, chemical reactions, or even the motion of massive bodies. It can also be a Tectonic earthquake explained by the elastic rebound theory.

A tectonic earthquake occurs when strains in rock masses have accumulated to a point where the resulting stresses exceed the strength of the rocks and sudden fracturing results. The cause can also be a volcanic earthquake caused by a slip on a fault near a volcano. Another cause is Artificial induction provoked by human activities, such as the injection of fluids into deep wells, the donation of large underground nuclear explosions, the excavation of mines, and the filling of large reservoirs and deep mining. Earthquakes have varied effects, including transformations in geologic features, damage to manufactured structures like buildings, and a negative impact on human and animal life.

Most of these effects occur on solid ground, but since most earthquake principles are located under the ocean bottom, severe effects often follow along the margins of oceans. The energy from an earthquake travels through Earth in vibrations called seismic waves. Scientists can measure these waves on seismometers. A seismometer detects seismic waves below the instrument and records them as zig-zags. Scientists can determine an earthquake's time, location, and intensity from the information recorded by a seismometer.

This record also provides information about the rocks the seismic waves traveled through. Seismic magnitude scales are used to describe the overall strength of an earthquake. These are differentiated from seismic intensity scales that categorize the intensity or severity of ground shaking caused by an earthquake at a specific location. Magnitudes are usually determined from measurements of an earthquake's seismic waves as recorded on a seismogram.

Magnitude scales range on what aspect of the seismic waves are measured and how they are measured. If the magnitude is 2.5 or less, usually the earthquake effects cant be felt. If it is 2.5 to 5.4, the earthquake is often felt and only causes minor damage. But if it was 5.5 to 6.0, slight damage to buildings and structures is done, and 6.1  to 6.9 can cause a lot of damage in intensely populated areas, but 7.0 to 7.9 can cause severe damage, and 8.0 or greater can destroy communities near the epicenter. Knowing what to do and how to protect ourselves during earthquakes is imperative. One way to immediately protect yourself is by DCH:

- DROP down onto your hands and knees before the earthquake knocks you down. This will protect you from falling and help you move if necessary.

- COVER your head and neck underneath a sturdy table or desk, and if there is no cover nearby, get down near an interior wall or low-lying furniture that won't fall on you and cover your head and neck with your arms. If possible, your entire body.

-  HOLD on to your cover or your head and neck until the shaking stops. Be prepared to move with your body if the shaking shifts around.

If you are inside a low-rise building, stay inside and do not run outside or change your location during the earthquake, and to reduce your chances of being hurt, you can take the following actions:

I- f possible, within the few seconds before the shaking intensifies, quickly move away from glass, hanging objects, or other large furniture that could fall and watch for falling objects.

- If available nearby, grab something to shield your head and face from falling debris and broken glass.

- If you are in the kitchen, quickly turn off the stove and take cover at the first sign of shaking.

- If you are in bed, hold on and stay there, protecting your head with a pillow. You are less likely to be injured staying where you are.

If you are in a high-rise building, follow the drop, cover, and hold on.

- Move away from windows and outside walls.

- Stay in the building.DO NOT use the elevators.

- The electricity may go out, and the sprinkler systems may come on.

- If you are trapped, stay calm. Try to get someone’s attention by tapping on hard or metal parts of the structure.

If you are outside, make sure to move away from buildings and utility wires. Go to an open area away from trees or any falling objects. And If you are in a moving vehicle, stop as quickly and safely as possible in a place away from buildings, trees, or any falling objects.