Photograph by Mosanori Kobayashi
Earthquakes, also called temblors, can be so tremendously destructive, it’s hard to imagine they occur by the thousands every day around the world, usually in the form of small tremors.
Some 80 percent of all the planet's earthquakes occur along the rim of the Pacific Ocean, called the "Ring of Fire" because of the preponderance of volcanic activity there as well. Most earthquakes occur at fault zones, where tectonic plates—giant rock slabs that make up the Earth's upper layer—collide or slide against each other. These impacts are usually gradual and unnoticeable on the surface; however, immense stress can build up between plates. When this stress is released quickly, it sends massive vibrations, called seismic waves, often hundreds of miles through the rock and up to the surface. Other quakes can occur far from faults zones when plates are stretched or squeezed.
Scientists assign a magnitude rating to earthquakes based on the strength and duration of their seismic waves. A quake measuring 3 to 5 is considered minor or light; 5 to 7 is moderate to strong; 7 to 8 is major; and 8 or more is great.
On average, a magnitude 8 quake strikes somewhere every year and some 10,000 people die in earthquakes annually. Collapsing buildings claim by far the majority of lives, but the destruction is often compounded by mud slides, fires, floods, or tsunamis. Smaller temblors that usually occur in the days following a large earthquake can complicate rescue efforts and cause further death and destruction.
Loss of life can be avoided through emergency planning, education, and the construction of buildings that sway rather than break under the stress of an earthquake.
Environment Quizzes
More About Earthquakes
-
Pictures: Winter Landscapes
Gorgeous shots of winter leave cool impressions.
-
13 Scariest Freshwater Animals
From the fearsome piranha to the mighty anaconda, see some of the world's most terrifying aquatic species.
-
Rays
See the stingers, shockers, and other amazing abilities of the flattened fish that have gracefully cruised Earth’s seas for 150 million years.
-
Japan Quake Shortened Day
The magnitude 9.0 earthquake that struck Japan last Friday was powerful enough to shorten Earth's day by 1.8 microseconds.
-
Japan Quake Not the "Big One"?
Though Friday's earthquake was the largest in Japanese history, it struck far from the Tokyo area, where in 1923 142,000 died.
-
Earthquakes 101
Learn the Science Behind Earthquakes
The Green Guide
Shop National Geographic
Advertisement
Green Living Hot Topics
-
Organic Air Fresheners
Avoid toxic chemicals and create a calming space.
-
Surprising Recyclable Household Items
With a little know-how, you can recycle more than you think.
-
Side Effects of Vegetarianism
Find out how to stay healthy and eat lower on the food chain.
More on Japan's Earthquake and the Pacific Ocean Tsunami
-
Japan's Energy Shortage
By summer, no nuclear plants will be operating in Japan, where mistrust reverberates one year after the world’s second-worst nuclear accident, at Fukushima Daiichi.
-
Photos: Japan Tsunami, Then and Now
A year ago Sunday, the March 11 Japan tsunami flooded highways, tossed boats and cars, and leveled cities. See what the region looks like now.
-
Where Will Next Tsunami Hit?
One year after the great Japan earthquake and tsunami, at least six other places worldwide are vulnerable to giant killer waves.
Special Ad Section
The World's Water
-
Visualizing Our Global Water Footprint
You might be surprised to see how the daily choices you make affect critical watersheds around the world.
-
How Much Water Per Pound?
How much water does it take to put beef, pork, wheat, and more on your plate? Explore our water footprint interactive and find out.
National Geographic Magazine
-
Photos: In the Field
Browse breathtaking images of life on the Serengeti.
-
A Thing or Two About Twins
Can the unique bond between identical twins be explained?
-
Visions of Earth
Browse stunning images of our planet as seen through a photographer's eye.
