Natural Disasters

Water and the Environment

Natural DisastersNatural Disasters

Natural disasters are a natural hazards that causes human loss. Just a few natural disasters include hydrological disasters, earthquakes, and volcanic eruptions.

What Is a Natural Disaster?

A natural disaster is a natural hazard, but a natural hazard is not necessarily a natural disaster. A natural disaster becomes a natural hazard when it occurs near vulnerable human populations. Natural disasters kill people and cause financial damage. For example, an earthquake that strikes an uninhabited place is a natural hazard, but not a natural disaster because it doesn’t kill people or destroy human property. An earthquake that strikes San Francisco, however, is a natural disaster. The amount of damage that a natural disaster creates depends on people’s resilience, their ability to withstand and resist the disaster. Natural disasters come in a variety of forms.

Hydrological Disasters

Hydrological disasters are natural disasters caused by water. Hydrological disasters include floods, tropical cyclones, and tsunamis. Floods are often created by tropical cyclones, which produce storm surge. Tsunamis are caused by underwater earthquakes. Japan’s 2011 Tohoku earthquake and accompanying tsunami is estimated to have killed up to 25,000 people.


An earthquake is a shaking of the Earth’s crust that happens when tectonic plates collide. These shakings differ in magnitude depending on the force of the tectonic plates’ collision. The underground place where the tectonic plates collide is called the “focus.” The point directly above the focus, which suffers the most damage, is called the “epicenter.” An earthquake alone won’t usually kill people or wildlife. However, earthquakes usually trigger secondary events that do cause damage. Earthquakes make buildings collapse and cause fires and tsunamis. These secondary events are what cause earthquakes to be perceived as natural disasters.  Societies can lessen their vulnerability to earthquakes by monitoring underground activity, warning people when earthquakes are going to occur, planning evacuations, and by building safer buildings and safety systems.

Volcanic Eruptions

Volcanic eruptions can destroy their surroundings in several ways. The initial volcanic explosion can produce dangerous rock falls. The lava produced by volcanic eruptions may trickle down, destroying nearby buildings and plants. Volcanic eruptions also produce toxic ash clouds, which can settle over nearby places. Even the smallest quantities of ash are toxic if inhaled, and enough ash can collapse roofs. The most destructive part of a volcanic eruption is pyroclastic flows, collections of hot volcanic ash clouds that rush down slopes. Historians believe that pyroclastic flows destroyed Pompeii. Volcanic eruptions, however, are some of the most visually astounding kinds of natural disasters.