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15 Destructive Facts About Earthquakes
Natural events such as volcanic eruptions and meteor impacts can cause earthquakes.
The majority of naturally-occurring earthquakes are triggered by movement of the earth's plates.
The surface of the earth is made up of 20 constantly moving plates.
As the plates shift, tension is created, and as its strength increases it can cause the crust to break.
When a break occurs, the stress is released as energy that moves through the Earth in the form of waves. These waves are earthquakes.
An average of 20,000 earthquakes every year (about 50 a day) around the world.
A quake is considered major when it registers more than 7.0 on the moment magnitude scale. A magnitude of 3.0 or lower is nearly imperceptible.
Millions of earthquakes estimated to occur every year that are too weak to be recorded.
Almost 80 percent of all the planet's earthquakes occur along the rim of the Pacific Ocean, called the "Ring of Fire."
A region that encircles the Pacific Ocean and is home to 452 volcanoes (over 75 percent of the world's active and dormant volcanoes).
The earliest recorded earthquake is from 1831 B.C. in the Shandong province in China.
A weaker earthquake can cause more damage and death than a stronger earthquake if its epicenters is in or close to large cities.
The largest recorded earthquake in the world was a magnitude 9.5 in Chile on May 22, 1960.
Its seismic waves traveled around the world, and shook the entire earth for many days.
However, an earthquake in 1201 A.D. in the eastern Mediterranean is labeled the worst earthquake in history and claimed an estimated one million lives.
Earthquakes kill approximately 8,000 people each year and have caused an estimated 13 million deaths in the past 4,000 years.
An average earthquake lasts around a minute.
Aftershocks occur because the displaced fault line and crust is adjusting to the effects of the main earthquake.
Larger earthquakes can have aftershocks that last for years.
Tectonic plates move less than 3 inches (17 cm) per year.
However, a tectonic plate movement of just 20 cm is enough to set off a major earthquake, such as the 6.9 Kobe earthquake in 1995.
There are four types of faults: normal, reverse, thrust, and strike-up.
Nearly 2,000 years ago, a Chinese astronomer named Zhang Heng (A.D. 78-139) invented the world’s first earthquake detector.
It could detect earthquakes more than 370 miles (600 km) away.
An earthquake on the moon is called a moonquake. Moonquakes are normally weaker than earthquakes.
The San Andreas Fault is moving about 2 inches a year, about the same rate fingernails grow.
At this rate, San Francisco and Los Angeles will be next to each other in 15 million years.
Japan’s 9.0 earthquake in 2011 not only moved the island closer to the United States, it also shifted the planet’s axis by 6.5 inches.
This caused the planet to spin faster and shortening the day by 1.6 microseconds.
It also created a massive 186-mile long and 93 mile wide rift 15 miles under the ocean.