The measure for the severity of an earthquake is determined by the Richter scale, a logarithmic scale of the amount of energy released by the impact. An earthquake with a magnitude of 3 on this scale is almost always palpable. As of magnitude 5 is a strong earthquake, which causes moderate damage. An earthquake with a magnitude 7 or higher is heavy earthquake, which generally causes a large-scale destruction. Below are the top ten largest earthquakes since 1900.
Terms and Definitions
I am listing the terms used in this article with their definitions adapted from Wikipedia.
Earthquake : "An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves."
Tectonic Plates : "A tectonic plate (also called lithospheric plate) is a massive, irregularly shaped slab of solid rock, generally composed of both continental and oceanic lithosphere. Plate size can vary greatly, from a few hundred to thousands of kilometers across; the Pacific and Antarctic Plates are among the largest."
Epicenter : "The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates."
Oceanic Subduction : "In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate and sinks into the mantle as the plates converge."
Megathrust Earthquake : "Megathrust earthquakes occur at subduction zones at destructive plate boundaries, where one tectonic plate is subducted by another."
10. 1950: Assam, India, Tibet and China - 8.6 on the Richter scale
The Assam - Tibet earthquake is also called as the Assam earthquake or Medog earthquake. Took place on August 15, 1950 and showed a magnitude of 8.6 Mw. The epicenter of the quake was from Rima to Tibet. From there, damage was caused in Tibet and Assam.
A total of 1,526 people died. The Assam - Tibet quake was the largest known earthquake 60’s was not caused by a megathrust or an oceanic subduction. Instead, it was caused by the convergence of two continental tectonic plates
9. 1946: Aleutian Islands, Alaska, USA - 8.6 on the Richter scale
The earthquake in the Aleutian Islands took place on April 1, 1946. It was immediately followed by a tsunami in the Pacific ocean.The quake had a magnitude of 8.6 Mw and a depth of 25 kilometers. Killed 165 people (159 in Hawaii and 6 in Alaska) and made losses of 26 million dollars. The tsunami showed various destructive waves with a height of between about 15 and 40 meters. It destroyed the lighthouse "Scotch Cap" on Unimak Island. Since the tsunami was unusually strong in comparison with the magnitude of the earthquake, the earthquake of the Aleutian Islands is classified as a tsunami earthquake. Following the disaster, the Seismic Sea Wave Warning System was created, which in 1949 became the Pacific Tsunami Warning Center.
8. 1965: Rat Islands, Alaska, USA - 8.7 on the Richter scale
On February 4, 1965 the Aleutian trembled again, this time with an epicenter in the Rat Islands. The quake had a magnitude of 8.7 Mw and caused a tsunami of more than ten meters high on Shemya Island fortunately there were no serious consequences. Studying the development of the tsunami, it was suggested that the earthquake was due to the three different sub events responsible for the shifting of tectonic plates. Two months later, the quake was moreover followed by a second major earthquake with a magnitude of 7.4 Mw This quake was caused by the "push back" of the tectonic plates that the 1st quake caused at the Rat Islands.
7. 2010: Bio-Bio, Chile - 8.8 on the Richter scale
The earthquake in Chile is still fresh in our memory. They took place on February 27, 2010 and had a magnitude of 8.8 Mw Intense tremors lasted up to three minutes long and were felt in six Chilean regions (from Valparaiso in Araucania in the north to the south). As the quake struck about 80% of the Chilean population. Thereby taking 525 lives and 9% of the affected population lost their house. The quake also caused a tsunami in south-central Chile that destroyed several coastal cities. Insurers estimate that the quake of Bio-Bio Chile's has brought an economic loss between fifteen and thirty billion dollars.
6. 1906: Ecuador, Columbia - 8.8 on the Richter scale
This earthquake took place on 31st January 1906 - had a magnitude of 8.8 Mw and caused a destructive tsunami that made at least 500 victims along the coasts of Columbia. The epicenter was just off the coast of Ecuador, near Esmeraldas. The concussion occurred along the boundaries of tectonic plates of Nazca and South America. Presumably it was caused by the subduction of the Nazca plate beneath the South American plate. After all, the region has a history of tremors caused by these plates.
5. 2011: Pacific Tōhoku Region, Japan - 9 on the Richter scale
The Tohoku earthquake is given the nickname of 'Great East Japan Earthquake’. They took place on Friday, March 11, 2011 and had a magnitude of 9.0 Mw The epicenter was situated about seventy kilometers east of the Oshika Peninsula. Hypocenter was located about thirty kilometers below sea level. The Tohoku earthquake was the largest earthquake ever in the Japanese region, since the beginning of the modern measurements in 1900. It caused a tsunami with waves up to 40.5 meters high.Estimates of damage were between 14.5 and 34.6 billion dollars.
In the area close to the epicenter were as many as four nuclear power plants: Onagawa, Tokai Fukushima I and Fukushima II. Through a series of accidents in the central Fukushima I, a significant amount of radioactive material was leaked and the nuclear emergency was declared. The tsunami destroyed the backup power supply, thus cooling the nuclear reactors failed. In three nuclear reactors, a meltdown of the reactor cores occurred. More than 200,000 people were evacuated.
4. 1952: Kamchatka, Russia - 9 on the Richter scale
The Kamchatka earthquake of November 4, 1952 was one of three quakes that have so far taken place on the shores of the eastern Russian peninsula. The two other major earthquakes were due to megathrust dating from 1737 and 1923 each with a resulting tsunami. Megathrusts are the worst kind of earthquakes. The quake of Kamchatka had a magnitude of 9.0Mw.
3. 2004: Indian Ocean, Sumatra, Indonesia - 9.1 on the Richter scale
This earthquake was also an undersea megathrust. They took place on Sunday, December 26, 2004 and had an epicenter near the western coast of Sumatra, Indonesia. The series of tsunamis that occurred there, also known as the Christmas tsunami or the Boxing Day Tsunami. The quake was caused by the subduction of the Indian plate with the Burmese nature ground plate. The disaster took away the lives of more than 230,000 people in fourteen countries. Thus, it became one of the deadliest disasters in the history of mankind . It lasted between 8.3 and 10 minutes. The Sumatra quake had a magnitude between 9.1 and 9.3 Mw
2. 1964: Prince William Sound, Alaska, USA - 9.2 on the Richter scale
On Good Friday, March 27, 1964, the Great Alaskan earthquake occurred. With a magnitude of 9.2 Mw, lasting almost three minutes remains to this day as the most powerful earthquake in the history of the USA and North America. One of the consequences, a tsunami of 8.2 meters high, destroyed the village of Chenega and killed 23 of its 68 residents. It was also a megathrust. It was caused by the subduction of the oceanic plate under a continental plate.
1. 1960: Valdivia, Chile - 9.5 on the Richter scale
The shock on Sunday, May 22, 1960 remains to this day the largest earthquake ever. It had a magnitude of 9.5 Mw. The tsunami that followed brought damage to Chile, Hawaii, Japan, the Philippines, New Zealand, Australia and the Aleutian Islands. The epicenter was near Lumaco, south of Santiago. Because the scale of this earthquake was so large, the death toll from the disaster remains uncertain until today. Numbers vary between 2231 and 6000 deaths. The monetary damage was estimated between 2.9 and 5.8 billion dollars.