What is the theory of plate tectonics?
The earth's surface is made up of constantly moving tectonic plates which fit together like a jigsaw puzzle. These sit atop a mantle of molten rock which is in constant motion.
What causes earthquakes?
As the tectonic plates move slowly on the molten interior they ‘grate and tug’ against each other at plate boundaries. This builds up of stress within the rocks. The sudden release of this pressure causes seismic waves which make the ground shake. That’s how earthquakes begin!
How do we measure earthquakes?
The Richter Scale is the most well-known way of measuring an earthquake’s strength, but most seismologists prefer the Moment Magnitude Scale which is based on the distance the fault has moved and the force required to move it. The scale is logarithmical so for each whole number you go up, the magnitude of the earthquake is amplified by 10 e.g. a magnitude 5 earthquake is 10 times stronger than a magnitude 4 quake.
Earthquakes happen every day
Earthquakes occur every day around the world, normally in the form of small tremors. Across the globe, an average of 20,000 earthquakes every year are recorded by the National Earthquake Information Center (NEIC) records.
Where do most earthquakes happen?
The vast majority occur along plate boundaries. Approximately 80% of earthquakes occur along the edge of the Pacific Ocean, called the "Ring of Fire", the world’s most active earthquake belt.
World’s deadliest earthquake
The world’s deadliest earthquake is thought to have occurred on 23 rd January 1556 in Shaanxi, China. The earthquake had an estimated magnitude of 8.0 on the Richter Scale, killing almost one million people.
World’s most powerful earthquake
The most powerful earthquake recorded achieved a magnitude of 9.5 on 22 nd May 1960 in southern Chile. 1,655 people were left dead and 3,000 injured, with 2 million homeless. An ensuing tsunami caused $550m worth of damage in Chile and killed a further 231 people as five-metre waves struck Hawaii and the Japanese and the Philippine coasts.
Undersea earthquake
On 26th December 2004, a magnitude 9.1 undersea earthquake beneath the Indian Ocean caused a series of destructive tsunamis. The 100-foot waves hit the coasts of most landmasses bordering the Indian Ocean, killing more than 225,000 people in 11 countries.
Largest UK earthquake
The largest known British earthquake was in 1931 near the Dogger Bank, 60 miles off the east coast of England. While the earthquake’s epicentre was offshore, with a magnitude of 6.1 it was powerful enough to cause minor damage to buildings.
Reducing the effects of earthquakes
There is currently no reliable method of accurately predicting the time, place and magnitude of an earthquake. Deaths as a result of earthquakes can be avoided through emergency planning, education, and the construction of earthquake resistant buildings that sway rather than break.
Infographic by: rayburntours.com