What are the causes of earthquakes and which were the strongest tremors?
Earthquakes are known to be one of the most terrifying and destructive natural disasters in the world.
But how do earthquakes occur, and when were they recorded the strongest?
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What causes earthquakes?
The earth’s crust is made up of different parts called tectonic plates.
These plates fit together like a jigsaw and move continuously at the rate of a few centimeters per year, in different directions and at different speeds.
It is common for the plates to slide over each other, collide and pull away from each other.
As the plates continue to move in different directions for long periods of time, friction causes a buildup of energy.
Eventually, it becomes so large that energy is released, which creates a shock wave – an earthquake.
If the earthquake occurs under the ocean, it can create a series of huge waves, called a tsunami.
Earthquakes happen every day around the world, some are so small that they can only be detected using specialized equipment.
Others can be powerful enough to damage and destroy towns and villages.
The size of such earthquakes would be measured on the Richter magnitude scale.
There are earthquakes in the UK, but they are rare and so small that most people don’t feel them.
What have been the strongest earthquakes of all time?
5. Kamchatka, earthquake in Russia (1952)
On November 4, 1952, at 16:58 GMT (04:58 local time), a massive earthquake struck off the coast of the Kamchatka Peninsula in the far east of Russia.
Measuring 9.0 on the Richter scale, it produced a large destructive tsunami across the Pacific with waves reaching 15 meters – causing extensive damage to the Kamchatka Peninsula and the Kuril Islands.
The earthquake killed around 10,000 to 15,000 people.
4. Tōhoku earthquake (2011)
On March 11, 2011 at 2:46 p.m. GMT (5:46 a.m. local time), a massive underwater earthquake occurred off the coast of Japan.
The 9.1 earthquake triggered a tsunami – producing waves up to 40.5 meters high.
The waves traveled inland up to 6 miles and caused extensive and severe structural damage in northeastern Japan.
On March 10, 2015, it was announced that confirmed casualties were 15,894 dead, 6,152 injured and 2,562 missing.
3. Sumatran earthquake (2004)
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On Boxing Day 2004, one of the deadliest natural disasters in recent history occurred.
The 2004 Sumatran earthquake, also known as the 2004 Indian Ocean earthquake, struck off the west coast of Sumatra, Indonesia.
It created the longest fault length of all recorded earthquakes – spanning a distance of 1,500 km, had the longest fault duration ever – between 8.3 and 10 minutes, and produced a tsunami with waves 30 m high.
It vibrated the entire planet up to 1 cm and caused up to a quarter of a million deaths.
2. Great earthquake in Alaska (1964)
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The Great Alaska Earthquake of 1964, also known as the Good Friday earthquake, occurred at 5:36 p.m. local time (1:36 a.m. GMT the following day) on Friday, March 27 in the Prince William Sound area of Alaska.
It lasted approximately 4.5 minutes and is the strongest recorded earthquake in US history.
The 9.2 earthquake triggered tsunamis felt in Alaska, Oregon and California.
A total of 139 people are believed to have died, 15 of them from the earthquake itself.
1. Valdivia earthquake (1960)
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Also known as the Great Chilean Earthquake, it is the strongest earthquake on record, measuring 9.5 on the Richter scale.
The earthquake struck on May 22 at 7:11 p.m. GMT (3:11 p.m. local time), about 100 miles off the coast of Chile – parallel to the city of Valdivia.
It lasted about 10 minutes and triggered a huge tsunami with waves up to 25m.
The total number of deaths from the earthquake and subsequent tsunamis was estimated to be between 1,000 and 6,000, with around 3,000 injured.