Earthquakes – How do They Occur and what is the Danger

Earthquakes are something that occurs around the world. It seems no matter where people live there is the possibility of an earthquake occurring. Some earthquakes that occur are mild tremors that do minimal to no damage whereas others are catastrophic. What causes earthquakes is a question asked by many. People unfamiliar with earthquakes might not understand the full extent of the potential danger associated with earthquakes. To have a better handle on how to deal with earthquakes it is important to understand why they occur and what danger they pose to people in the area when they happen.

What Causes Earthquakes

Many people may understand from movies and television shows that earthquakes are the shaking of the earth. The shaking can range from relatively unnoticeable movement to violent and destructive shaking. This shaking can occur for a matter of seconds to several minutes. The shaking, or rolling, of the earth is a direct result of the movement of tectonic plates beneath the earth’s surface.

The grinding and scraping of the tectonic plates against one another coupled with the push of the earth’s outer layer create a tremendous amount of stress. As this stress continues to build eventually the plates and rocks slip. In that instant, all of the stress and energy is released causing it to travel through the earth’s crust in waves. All of this movement leads to shaking of once solid, stable ground.

Potential Dangers

The potential dangers of earthquakes vary depending on the earthquake’s magnitude. The most dangerous are earthquakes with a magnitude ranging from seven to 10. Earthquakes with a magnitude of five or less either do minimal damage or go completely unnoticed.

In some respects, earthquakes pose no threat to people. People are safe from earthquakes when they are in a location where nothing can fall on them, the ground stays together, and there is no threat of a tsunami occurring. The following are serious dangers associated with earthquakes.

  • Liquefaction – This occurs when an earthquake takes place where the soil is loosely packed and waterlogged due to floods. When this occurs, the once solid land can have the same consistency of quicksand.
  • Landslides – These occur either due to soft earth breaking free or excessive water creating mudslides.
  • Flooding – When earthquakes take place near dams, levees and they break there is the potential for flooding.
  • Fire – Fires occur due to downed power lines, broken gas lines, as well as wood or coal stoves tipped by the shaking. Broken or inaccessible fire hydrants increase the problems of fire control.
  • Tsunamis – Earthquakes that occur on the ocean’s floor or trigger underwater landslides can trigger catastrophic tsunami waves.

There are earthquakes that occur every day that rank less than three in magnitude. These are so slight most people do not feel them. Most people would be unaware of them if not for the tracking of these movements by geologists with a seismograph. Understanding why earthquakes occur and understanding the potential dangers can help people deal with them. It is essential to have an emergency plan in place as well as emergency supplies in the event of a major earthquake. Unfortunately, unlike tornados and hurricanes, there is no way to predict when and where they might occur.

Resources:

  • https://www.fema.gov/why-earthquakes-occur
  • http://www.geo.mtu.edu/UPSeis/hazards.html
  • http://earthquake.usgs.gov/learn/topics/megaqk_facts_fantasy.php
  • http://www.livescience.com/21486-earthquakes-causes.html

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