- Earthquakes kill approximately 8,000 people each year and have caused an
estimated 13 million deaths in the past 4,000 years.d
- The moment magnitude scale (MMS) replaced the 1930s-era Richter scale in
the 1970s as the method of measuring the size of earthquakes in terms of
energy released.a
- In Japan mythology, a giant catfish called Namazu is responsible for earthquakes.b
- The Indian Ocean earthquake in 2004 generated enough energy to power all
the homes and businesses in the United States for three days.d
- An average earthquake lasts around a minute.j
Aftershocks can occur years after a main earthquake
- Aftershocks occur because the displaced fault line and crust are adjusting
to the effects of the main earthquake. Larger earthquakes can have aftershocks
that last for years.f
- Shock waves produced by Rayleigh waves or waves that roll through the Earth’s
surface—in contrast to side-to-side waves or Love waves—can travel far enough
upward to cause a disturbance in the ionosphere. The ionosphere is the layer
of Earth’s atmosphere about 50-300 miles (80-480 km) above Earth’s
surface.b
- Parkfield, California, is known as “The Earthquake Capital of the
World” and has a bridge that spans two tectonic plates.b
- Earthquakes are mostly caused by geological faults, but they can also be
caused by landslides, nuclear testing, mine tests, and volcanic activity.a
- The “focus” or “hypocenter” is the earthquake’s
initial point of rupture. Its “epicenter” is the point at ground
level above the hypocenter.d
- In ancient Greece, people believed that the god of the sea, Poseidon, caused
earthquakes. When he was angry, Poseidon would strike the ground with his
trident and set off an earthquake. His unpredictable, violent behavior earned
him the nickname “Earth-Shaker.”a
- More earthquakes happen in the Northern Hemisphere than in the Southern
Hemisphere.b
- In Hindu mythology, Earth is held in place by eight gigantic elephants,
all balanced on the back of turtle, which itself stands on the coils of a
snake. If any of these animals shift or move, an earthquake occurs.b
- The worst avalanche triggered by an earthquake occurred in Peru in 1070.
A 250-foot (850-meter) wave of ice, mud, and rock fell down the mountain
in Huascaran at 250 miles (400 km) per hour. It carried away entire villages
and killed more than 18,000 people.j
- The world’s worst landslide started by an earthquake occurred in 1920
in the Kansu province in China. The landslide killed about 200,000 people.j
- The highest tsunami caused by an earthquake happened in Japan in 1771. A
tsunami 278 feet (85 meters) high struck Ishigaki Island.j
- The shape of a pagoda is known for resisting damage from earthquakes.j
- The term “tectonic” is related to the word “texture” and
is from the Greek tektonikos which means “pertaining to building,” from
the Proto-Indo-European base *tek, “to make.”a
Even a small plate movement can trigger major earthquakes
- 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.d
- Scientists developed the theory of plate tectonics in the mid-twentieth
century.d
- There are four types of faults: normal, reverse, thrust, and strike-up.f
- 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.f
- The 1906 earthquake in California was before the Richter scale, but scientists
estimate it would rank as a 7.8. As much as 90% of the damage in San Francisco
was from fires caused by cracked gas pipes. San Francisco burned for three
days and nights.a
- The 1906 California earthquake was one of the first major disasters to be
recorded by photography.b
- 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.b
- Nearly 80% of Earth’s largest earthquakes occur near the “Ring
of Fire,” which is a horseshoe-shaped region in the Pacific Ocean where
many tectonic plates meet. The second-most earthquake-prone area is a region
called the Alpide Belt, which includes countries such as Turkey, India, and
Pakistan.g
- Earthquakes can set off volcanoes, as was the case in the 1980 Mount St.
Helens eruption and the Mount Etna eruption in 2002.g
- An earthquake in A.D. 1201 in the eastern Mediterranean is labeled the worst
earthquake in history and claimed an estimated one million lives.j
The Transamerica Pyramid swayed over 12 inches in the 1989 earthquake
- The 853-foot (260-meter) high Transamerica Pyramid in San Francisco has
been designed to withstand strong earthquakes.j
- Earthquakes occur only in the Earth’s crust. Deep earthquakes originate
in crust that is sliding down beneath another tectonic plate. The most devastating
earthquakes are those that are strong and shallow with the focus point less
than 20 miles (32 km) underground and that occur in highly populated areas.g
- Scientists think that animals may sense weak tremors before a quake. Other
scientists think that animals may sense electrical signals set off by the
shifting of underground rocks.d
- The ancient Greeks believed that earthquakes were caused by winds rushing
out from caves inside Earth.b
- The 2004 Indian Ocean earthquake lasted nearly 10 minutes—the longest
on record.b
- Englishman John Milne invented the seismograph in 1880.g
- American scientist Charles Richter invented the Richter scale in 1935.j
- There are about 1,300,000 earthquakes per year (two per day) with
magnitudes of 2.9 or lower.j
- Approximately one earthquake with a magnitude of 8.0 or higher occurs per
year.f
The 1960 Great Chilean earthquake’s rupture zone was over 497 miles long
- The largest earthquake in recent history was a 9.5 and occurred in Chile
in 1960. It caused giant ocean waves as far as 6,000 miles (10,000 km) away.b
- The largest earthquake in the U.S. on record was a 9.2 quake that occurred
in Alaska in 1964.a
- The speed of the fastest seismic wave is 225 miles (360 kilometers) per
hour.h
- An earthquake can release hundreds times more energy than the nuclear bomb
that was dropped on Hiroshima in Japan in 1945.h
- Before an earthquake, ponds and canals may give off a strange smell. This
is caused by the release of gases underground. The temperature of ground
water can also become warmer.h
- An earthquake under the ocean can cause a tsunami, which travels outward
in all directions up to 600 miles (970 km) per hour, the speed of a jet.
When the tsunami reaches the shoreline, it suddenly rolls up to heights of
over 100 feet (30 meters) causing massive destruction.b
- An earthquake on the moon is called a moonquake. Moonquakes are normally
weaker than earthquakes.a
- Though the ground moved for only about 20 seconds during the 1995 Kobe,
Japan, earthquake, more than 5,000 people were killed, 300,000 people were
left homeless, and more than 100,000 buildings were destroyed.b
- The earthquake in Lisbon, Portugal, in 1775 caused waves on the surface
of Scotland’s Loch Ness, more than 1,240 miles (2,000 km) away.b
- The 1964 Alaska 9.2 quake lasted four minutes and dropped streets 20 feet
(6 meters) below normal. It caused flooding on the coast of Hawaii, more
than 3,100 miles away.a
- The first recorded earthquake in California was in 1769 by Gaspar de Portola,
an explorer and Spanish military officer.a
The San Andreas fault extends at least 20 miles vertically into the Earth
- 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.b
- The most earthquake-prone state is Alaska.h
- The earliest recorded earthquake is from 1831 B.C. in the Shandong province
in China.h
- Aristotle was the first to note that soft ground shakes more than hard ground.b
- Japan is one of the most earthquake-prone nations in the world. Thousands
of earthquakes occur in Japan every year, but most of them are very weak.a
- In 2006, geologists found three new faults in northern California. The faults
run under small towns and vineyards in Mendocino County.b
- The San Andres is one of the longest fault zones in the world. It is a strike-slip
fault and runs over 800 miles (1,280 km) from San Francisco through southern
California to Mexico. The San Andres fault is not just one fault but it is
actually made up of many faults.g
- The 9.0 earthquake that struck Japan March 11, 20110 was the worst earthquake
in Japan’s history. It created a tsunami with waves
as high as 30 feet (10 meters) and severely damaged nuclear power plants.i
Japan is one of the most earthquake-prone countries in the world
- 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.e
- The devastating 2011 earthquake in Japan created a massive 186-mile long
and 93 mile wide rift 15 miles under the ocean.e
- Japan’s massive 2011 earthquake shifted the earth’s mass toward
the center, causing the planet to spin faster and shortening the day by 1.6
microseconds. The 2004 Sumatra quake shorted the day by 6.8 microseconds.e
- Because earthquake-prone Japan had placed high-tech sensors around the country
after its 1995 quake, Japan’s 2011 earthquake is the best-recorded
earthquake in history.e
The Five Strongest Earthquakes Since 1900 d, e
Place |
Year |
Strength (MMS) |
Valdivia, Chile |
1960 |
9.5 |
Prince William Sound, Alaska |
1964 |
9.2 |
Sumatra, Indonesia |
2004 |
9.1 |
Sendai, Japan |
2011 |
9.0 |
Kamchatka, Russia |
1952 |
9.0 |
The Top Five Deadliest Earthquakes in History c
Place |
Year |
Casualties |
SW Syria |
1201 |
1,100,000 |
Tangsha, China |
1978 |
655,237 |
Ganja, Azerbaijan |
1139 |
300,000 |
China |
1662 |
300,000 |
Earthquake Time Line d,j
132 AD |
Zhang Heng invents the first earthquake detector |
1556 AD |
A massive earthquake hits the Shaanxi province in China, killing over 800,000 people |
1775 AD |
Triggered by an earthquake, a massive tsunami hits Lisbon, Portugal, with waves over 50 feet high |
1885 AD |
Britih geologist John Milne invents the first modern seismograph for measuring earth tremors |
1906 AD |
The Great San Francisco Earthquake kills nearly 3,000 people |
1923 AD |
The Great Kanto Erthquake hits Tokyo, Japan, killing more than 140,000 people and destroying 360,000 buildings |
1935 AD |
American Charles Richter invents the Richter scale to measure earthquake magnitude |
1960 AD |
In May, the largest earthquake ever recorded, meausring 9.5 on the Ricther scale, hit Chile, causing tsunamis that affect Chile, Peru, Hawii, and Japan |
1970 AD |
An earthquake measuring 7.7 strikes Peru, causing massive mudslides and avalanches in the mountains. 18,000 people are killed |
1978 AD |
An earthquake measuring 7.8 hits Tangshan, China. Over 242,000 people are crushed to death |
1988 AD |
An earthquake measuring 6.9 hits Armenia, causing newly built apartments to collapse, killing 25,000 |
1995 AD |
In Kobe, Japan, 5,5000 people die in 7.2 earthquake |
1999 AD |
An earthquake in Turkey kills 17,000 people |
2001 AD |
An earthquake in Gujarat, India kills 20,000 people |
2003 AD |
An earthquake in Iran kills 26,000 people and destroys the ancient city of Bam |
2004 AD |
An earthquake measuring between 9.1 and 9.3 strikes off the west coast of Sumatra, Indonesia, triggering a massive tsunami that kills over 230,000 people in fourteen countries |
2005 AD |
On October 8, a 7.6 earthquake in Pakistan and parts of Kashmir kills over 86,000 people |
2010 AD |
Over 230,000 people die in Haiti after a 7.0 earthquake |
2011 AD |
On March 11, 2011, a 9.0 earthquake strikes off the east coast of Honshu, Japan, triggering deadly tsunamis |
-- Posted April 14, 2011
References
a Bolt, Bruce A. 2006. Earthquakes. 5th Ed. New York,
NY: W.H. Freeman Company.
b Colson Mary. 2006. Shaky Ground: Earthquakes. Chicago,
IL: Raintree.
c Dutch, Steven. “Top
Ten Earthquakes and Volcanic Eruptions.” May 2010. Accessed: March 24, 2011.
d Fradin, Judy and Dennis. 2008. Earthquakes: Witness
to Disaster. Washington D.C.: National Geographic.
e Goodwin, Liz. “Japan’s Earthquake Shifted
Balance of the Planet.” Yahoo!News. March 14 2011. Accessed: April
2, 2011.
f Page, Jake and Charles Officer. 2004. The Big One.
New York, NY: Houghton Mifflin Company.
g Redfern, Martin. 2003. The Earth: A Very Short Introduction.
New York, NY: Oxford University Press.
h Richards, Julie. 2001. Quivering Quakes. Broomall,
PA: Chelsea House Publishers.
i “Travel
Health Precautions: 2011 Earthquake Tsunami, and Radiation Release in Japan.” CDC. March 18,2011. Accessed: April
2, 2011.
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