Determining the largest earthquakes can be a difficult task, since it depends on how the question is defined. Some people might consider the largest to be those that registered highest on the Richter scale, while others might consider the number of deaths or cost of damages. Additionally, the Richter scale was invented in 1934, so it may be difficult to compare earthquakes that occurred prior to that time with later, more accurate readings.
Earthquakes that occurred before the 20th century are particularly difficult to rate. A major earthquake in Pompeii in the year 62 CE, seven years before the volcanic eruption that would destroy the city, was said to have caused considerable damage. In 1556, an earthquake in Shaanxi province in China was reported to have killed at least 830,000 people, and it is still considered the deadliest quake in history. The New Madrid quake, which struck the US in southern Missouri in 1811, caused the Mississippi River to flow backward. There have been many other severe earthquakes throughout history, the severity of which will likely never be accurately known.
More recent earthquakes have been more accurately measured, and the magnitude of those that occurred before 1934 can be estimated. The ten largest earthquakes, according to measured or estimated magnitude recorded since 1900, are as follows:
| Rank | Date | Location | Magnitude | Estimated Deaths/Damages (USD) |
|---|---|---|---|---|
| 1 | 1960 | Chile | 9.5 | 1,655/$6 million |
| 2 | 1964 | Alaska | 9.2 | 128/$300 million |
| 3 | 2004 | W. Sumatra | 9.1 | 227,898/estimated in the billions |
| 4 | 2011 | Japan | 9.0 | more than 12,000/unknown |
| 5 | 1952 | Russia | 9.0 | none reported/$1 million |
| 6 | 2010 | Chile | 8.8 | 521/$30 billion (est.) |
| 7 | 1906 | Ecuador | 8.8 | 500-1,500/unknown |
| 8 | 1965 | Alaska | 8.7 | none reported/$10,000 |
| 9 | 2005 | N. Sumatra | 8.6 | 1,300/unknown |
| 10 | 1957 | Alaska | 8.6 | none reported/$5 million |
Of the ten largest recorded since 1900, four occurred on or around the continent of Asia, three in North America, and three in South America. The Chilean Earthquake of 1960, largest in terms of measured magnitude, caused damage as far away as Japan, Hawaii, and coastal California.
In terms of lives lost, the 2004 Western Sumatra quake, also known as the 2004 Indian Ocean Earthquake, resulted in the highest death toll for recorded quakes since 1900. The earthquake itself was reportedly felt in regions as far away from the epicenter as Malaysia, Singapore, and Bangladesh. The vast majority of lives were lost in Indonesia due to resulting tsunami, which also hit land masses bordering the Indian Ocean, such as Sri Lanka, India, and Thailand. It spawned further quakes as far away as Alaska.
Most of these earthquakes triggered a tsunami that resulted in death and/or damages to property. Even the 1950 Tibet Earthquake, which at 8.6 magnitude has just been pushed off the top 10 list, resulted in hundreds of deaths due to river flooding. Eight days after the Tibet quake, a landslide, which had formed a natural dam in the Subansiri River immediately after the quake, broke loose, reportedly killing an additional 500 people.
As recorded by the United States Geological Survey, the largest all centered in what is known as the Pacific Rim of Fire. The geological region contains more than 75% of the Earth’s dormant and active volcanoes and is home to about 80% of the biggest earthquakes ever recorded. The region itself runs roughly from the coast of New Zealand, northward along the eastern coast of Asia, across the North Pacific to Alaska, and southward down the entire West Coast of North and then South America.
The Pacific Rim of Fire touches the edges of seven separate tectonic plates: Pacific, Indo-Australian, Eurasian, North American, Cocos, Nazca, and Antarctic. Tectonic plates are huge pieces of the Earth's crust that rest on top of the mantle, a hot, soft layer of compounds that causes the plates to move. It is the shifting of the plates that cause most earthquakes the planet experiences.