Types of natural calamities include hurricanes, earthquakes and tsunamis. Often, these calamities are connected such that one sets off another, as with earthquakes and tsunamis. Natural calamities are differentiated from human-made calamities, such as industrial accidents.
A hurricane is a storm system with sustained winds higher than 74 mph. At this level, the whirling storm develops an eye, which is an area of relatively calm weather at the center of a storm. Hurricane Katrina was one of the most devastating storms to hit landfall in the United States. It destroyed the city of New Orleans and caused near 1800 fatalities and billions of dollars of property damage along the Gulf Coast in 2005.
Earthquakes are violent vibrations of the earth's surface caused by the sudden movement of the tectonic plates. An earthquake releases a certain amount of seismic activity that can be measured to determine the magnitude of the event. Earthquakes can also be caused by volcanic activity and human actions, such as nuclear explosions.
In turn, undersea earthquakes can be the source of massive tsunamis that cause coastal devastation. A tsunami is a series of enormous waves caused by the displacement of water because of a disturbance. In 2004, a major earthquake off the coast of Indonesia led to a series of tsunamis that killed approximately 300,000 people.