# By: Roan and Caroline

by: www.dosomething.org

How Do Earthquakes Happen?

For most of history people didn't know what caused earthquakes, but in the mid 1960s people in the USA and Great Britain found out an Earthquake is when tectonic plates rub together. That is why the earth shakes. The earth's crust is made of many tectonic plates. The plates move when they rub together the crust is moved.

Tectonic Plate Map

Scolastic Teachers

Magnitude

Magnitude is used to measure an earthquakes intensity. Unfortunately many scales such as the Richter Scale do not give good estimates for large magnitude (8+) earthquakes. Only moment magnitude can measure large magnitude (8+) earthquakes well. Magnitude is on a scale from 0.1 - 10.

1 Magnitude is like blowing up 6 ounces of TNT                                                                                                                                            8 Magnitude is like blowing up 6 tons of TNT                                                                                                                                          -Charles Richter

Magnitude Scale

2.5 or less: Usually not felt 900,000 each year

2.6 - 5.4: Causes minor damage 30,000 each year

5.5 - 6.0: Slight damage to buildings 500 each year

6.1 - 6.9: Can cause a lot of damage in heavily populated areas 100 each year

7.0 - 7.9: Serious damage 20 each year

8.0 + Huge earthquake 5-10 each year

3.9 or less: Minor

4.0 - 4.9: light

5.0 - 5.9: Moderate

6.0 - 6.9: Strong

7.0 - 7.9: Major

8.0 +: Great

http://poleshift.ning.com/m/blogpost?id=3863141%3ABlogPost%3A487732&maxDate=2012-03-22T10%3A11%3A10.929Z

Fault Lines

24/7 people all around the globe are watching for movement of the earth's tectonic plates and report them. Most earthquakes occur on the cracks of the earths crust (edge of a tectonic plate). They are called fault lines. Fault lines are were tectonic plates meet. they are called fault lines because they are where at least 2 tectonic plates meet that is where an earthquake is most likely to happen. Earthquakes happen when tectonic plates pressure builds and it slips out of place really fast making an earthquake. some fault slips make fissures.

Top 9 Famous Earthquakes

9. 2008 Sichuan Province, China

with a magnitude of 7.5 and a death toll of 80,000

8. 2005 Kashimir, Pacistan

with a magnitude of 7.6 and a death toll of 79,000

7. 2008 Sichuan Province ,China

with a magnitude of 7.9 and a death toll of 87,000

6. 1948 Turkmenistan

with a magnitude of 7.3 and a death toll110,000

5. 1923 Kanto Japan

with a magnitude of 7.9 and a death toll of 143,000

4. 1920 Haiyuan China

with a magnitude of 7.8 and a death toll of 200,000

3. 2004 Indian ocean tsunami

with a magnitude of 9.2 and a death toll of 227,000

Random Fact: The Tsunami released energy equivalent to 23,000 atom bombs

2. 1976 Tangshan, China

with a magnitude of 7.8 and a death toll 250,000

1. The deadliest earthquake ever record 1556 Shanix, China

with a magnitude of 8.6 and a death toll of...

830,000

Random Facts

Fact #1: Natural Events such as meteor impacts and volcanic eruptions can trigger earthquakes, but the majority of all earthquakes are caused by movement in tectonic plates

Fact #2: The largest earthquake had a magnitude of 9.5 in Chile May 22

Fact #3: An average earthquake lasts about 1 minute no matter how strong they are

Fact #4: the worst earthquake ever recorded was in 1201 AD and the death toll was around 1 million

Fact #5: Before an earthquake ponds and canals may give off a strange smell this is caused by a release of gases under ground

Fact #6: When an earthquake happens sometimes the water temputure rises

Fact #7: An earthquake on the moon is called a moonquake, moonquakes are normally weaker than earthquakes

Fact #8: An earthquake releases about as much energy as 10,000 atom bombs

Fact #9: More earthquakes happen in the northern hemisphere than in the southern hemisphere.

Fact #10: Dogs,cats,fish,and snakes can sense earthquakes before they happen. If they sense an earthquake, dogs will bark and run around, cats and snakes will be restless and fish will swim quickly and jump around.