Earthquakes are caused by forces deep within the Earth.
When the earth shakes, buildings can collapse and people can be buried inside.
An explosion is a rapid, violent release of energy.
Explosions can be caused by chemical reactions, such as inside an engine.
A spark can ignite a mixture of gases, and release energy for good or destructive purposes.
Accidents are often caused by people doing foolish things or by not being careful.
One major cause of accidents is driving too fast.
Accidents with fire can be very serious and can result in very painful injuries.
Epidemics are the rapid spread of a disease such as the flu or Ebola.
Throughout history, epidemics have killed millions of people.
Storms are caused by changes in the atmosphere resulting in high winds and heavy rain.
Thunderstorms are caused by electric charges in the atmosphere that produce lightning, which can cause forest fires.
Some storms cause flooding, and major damage to homes and cities.
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