Strong earthquakes (6.0 or above) are relatively rare events, but there are around 8,000 quakes classified as 'very minor' 91.0-2.0) every year.

The earth we live on is far from stable. We live on a thin and brittle crust which is floating on millions of cubic kilometres of molten, moving rock.

Convection currents in the mantle push and pull at this thin crust, forcing the continents to 'drift' in relation to each other.

As the mantle's rocks move, the continental plates snag and crash into each other causing shockwaves to ripple throughout the crust.

The U.S. Geological Surrvey has been recording the magnitude of earthquakes since 1899. Below are the most powerful quakes that we know about.

1. 22 May 1960 - Valdivia, Chile

Magnitude 9.5

The most powerful earthquake ever recorded caused tsunamis in Chile, Hawaii, Japan, the Philippines, eastern New Zealand, southeast Australia and Alaska. Estimates of the death toll range from 2,231 to 6,000. A further 2 million were left homeless after the 9.5 magnitude quake struck southern Chile.

2. 28 March 1964 - Prince William Sound, Alaska

Magnitude 9.2

The most powerful earthquake recorded in North American history devastated the Gulf of Alaska, caused landslides in Anchorage and raised outlying islands by 11 metres. The resulting tsunami reached 67 meters when it raked the shallow Valdez inlet and was responsible for most of the 131 deaths and $311m worth of damage.

3. 26 December 2004 - Northern Sumatra, Indonesia

Magnitude 9.1

The deadliest tsunami in history hit 14 countries across Asia and east Africa, triggered by the 9.1 magnitude quake off the west coast of Sumatra. It is one of the deadliest natural disasters in recorded history, with nearly 230,000 killed.

4. 11 March 2011 - Honshu, Japan

Magnitude 9.0

The most powerful earthquake to hit Japan, the earthquake triggered tidal waves up to 40 meters high that struck Japan's eastern shore, reaching as far as six miles inland. In addition to the 15,281 deaths the tsunami caused a number of nuclear accidents among the country's aging facilities.

5. 4 November 1952 - Kamchatka, Russia

Magnitude 9.0

The remote Russian peninsula was the epicentre of the quake, but it was the Hawaiian islands that were the worst hit as a series of tsunamis around the peninsula caused an estimated $1 million worth of damage. No deaths were recorded.

6. 27 February 2010 - Bio-Bio, Chile

Magnitude 8.8

As yesterday's quake demonstrated, the Bio-Bio region in Chile's south-central Pacific coast is a particularly unsettled seismological region. The most devastating tremor of recent times occurred in 2010 when a magnitude 8.8 quake shook the region for three minutes and generated a Pacific-wide tsunami. An estimated 723 people lost their lives, with a further 12,000 injured and more than 800,000 left homeless. The earthquake was so powerful that it shortened the day's length by 1.26 microseconds, and altered the Earth's rotation by 3 inches.

7. 13 January 1906 - coast of Ecuador

Magnitude 8.8

Striking in ocean floor off the Ecuador coast, the quake triggered a tsunami that killed between 500 and 1,500 people along the coastline stretching from Central America to San Francisco and reaching as far away as Hawaii.

8. 04 February 1965 - Rat Islands, Alaska

Magnitude 8.7

Alaska is particularly vulnerable to earthquakes given its location in one of the world's most active seismic zones, at the top of the Pacific Ring of Fire. The quake that hit off the Rat Islands chain generated a tsunami over 10 meters high. Due to the tremor's remote location there were no casualties - no accurate figures were available for the number of rat deaths.

9. 28 March 2005 - Northern Sumatra

Magnitude 8.6

Often referred to as the Nias Earthquake, the major quake off the west coast of northern Sumatra killed approximately 1,300 people and triggered wide-spread panic in a region that had been devastated by the massive tsunami generated by the 2004 earthquake. But this quake generated a relatively tiny tsunami that caused limited damage.

10. 15 August 1950 - Assam-Tibet

Magnitude 8.6

Emanating in Tibetan Rima the quake wrought destruction across India's Assam state. Seventy villages disappeared and 1.526 people were killed as landslides rendered parts of the landscape unrecognisable from the air. The tremor caused severe flooding in the area and a natural dam on the Subansiri River collapsed, releasing a seven-metre wall of water into the valley.