The nature of an earthquake
Earthquakes are caused by the sudden release of energy within some limited region of the rocks of the Earth. The energy can be released by elastic strain, gravity, chemical reactions, or even the motion of massive bodies. Of all these the release of elastic strain is the most important cause, because this form of energy is the only kind that can be stored in sufficient quantity in the Earth to produce major disturbances. Earthquakes associated with this type of energy release are called tectonic earthquakes.

What causes earthquakes?
The earth has four major layers: the inner core, outer core, mantle and crust. The crust and the top of the mantle make up a thin skin on the surface of our planet. But this skin is not all in one piece – it is made up of many pieces like a puzzle covering the surface of the earth. Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other. We call these puzzle pieces tectonic plates, and the edges of the plates are called the plate boundaries. The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults. Since the edges of the plates are rough, they get stuck while the rest of the plate keeps moving. Finally, when the plate has moved far enough, the edges unstick on one of the faults and there is an earthquake.

Responsibilities of individuals
Know the safe spots in each room–under sturdy tables, desks or against inside walls.
Know the danger spots–windows, mirrors, hanging objects, fireplaces, tall furniture.
Conduct practice drills. Physically place yourself and your children in safe locations.
Learn first aid and CPR ( cardiopulmonary resuscitation) from your local Red Cross Chapter or other community organization.
Decide where your family will reunite if separated.
Keep a list of emergency phone numbers.
Choose an out-of-state friend or relative whom family members can call after the quake to report whereabouts and conditions. Learn how to shut off gas, water and electricity in case the lines are damaged.
Check chimneys, roofs, and wall foundations for stability. Make sure your home is bolted to its foundation. Call a licensed contractor if there are any questions.
Secure water heaters and appliances that could move enough to rupture utility lines.
Keep breakable and heavy objects on lower shelves.
Secure hanging plants and heavy picture frames or mirrors (especially those hanging over beds).
Put latches on cabinet doors to keep them closed during shaking.
Keep flammable or hazardous liquids such as paints, pest sprays or cleaning products in cabinets or secured on lower shelves.
Maintain emergency food, water and other supplies, including medicine, first aid kit and