The earthquake of May 22, 1960, that struck the town of Valdivia in southern Chile is the most powerful ever recorded and has become known as the Great Chilean Earthquake. It is thought to have measured 9.5 on the moment magnitude scale (MMS). Two tectonic plates shifted by over 30 meters, releasing huge volumes of energy in seismic waves. Entire cities were reduced to rubble in just 10 minutes. About 6,000 people died and resulting tsunamis killed 130 people in Japan and more than 60 in Hawaii.

While the US was only marginally affected by that Chilean earthquake, four years later on Good Friday, it became the epicenter of the second most powerful quake ever recorded. The 9.2 magnitude Great Alaskan Earthquake lasted some four minutes and destroyed large parts of the infrastructure in southern and central Alaska. The state's largest city, Anchorage, sustained massive damage, with entire roads being destroyed. Post-quake tsunamis affected a series of coastal towns, with 139 people drowning in the ensuing floods. However, lives were saved due to the fact that it was Good Friday and many businesses were shut. There were also no children in the schools that collapsed.

In February 2023, Turkey and Syria were struck by earthquakes roughly 12 hours and 95 kilometers apart and measuring 7.8 and 7.7 on the MMS, the largest in Turkey in over eight decades. The earthquakes killed more than 50,000 people in Turkey and at least 8,400 in Syria and left an estimated 1.5 million people homeless.

Earthquakes and tsunamis

Tsunamis often occur when the earth quakes below or near the sea. They can cause fatalities far from a quake's epicenter. Nobody died directly in the 9.1 magnitude Indian Ocean quake, also known as the Sumatra-Andaman quake of 2004, but the tsunami that it unleashed, with tidal waves of up to 30 meters, killed over 240,000 people in 14 countries in South and Southeast Asia. It was thus one of the deadliest quakes in recorded history.

In 2011, an undersea earthquake in the Tohoku region of Japan triggered a tsunami that in turn caused the worst nuclear disaster since the Chernobyl accident of 1986. Measuring 9.1 on the moment magnitude scale, the quake caused powerful tsunami waves that flooded an area on Japan's Pacific coast greater than 500 square kilometers (193 square miles). 

Some 22,000 people were killed and about 400,000 buildings collapsed or were completely destroyed. A 14-meter-high wave hit the nuclear power plant in Fukushima, causing meltdowns in three reactors and radioactive discharge that led to many countries revising their relationship with nuclear power.

Two deadly quakes in China 

On January 23, 1556, an earthquake occurred in the Shaanxi province of central China. It was described as follows by chroniclers of the time: "Various misfortunes took place. Mountains and rivers changed places and roads were destroyed. In some places, the ground suddenly rose up and formed new hills, or it sank abruptly and became new valleys. In other areas, a stream burst out in an instant, or the ground broke and new gullies appeared. Huts, official houses, temples and city walls collapsed all of a sudden."

Some 830,000 people are thought to have been killed in the quake, which is estimated to have measured 8.25 on the MMS, and its aftermath. It is the deadliest recorded quake in history.

Probably the second deadliest earthquake in recorded history and the worst of the past 100 years also occurred in China. At 3:42 local time on July 28, 1976, a 7.1 magnitude quake almost destroyed the city of Tangshan, which today has a population of over 7 million. The epicenter was 20 kilometers southwest of Tangshan, but the tremors were felt 140 kilometers away in Beijing. Over five million homes were uninhabitable afterward, and hundreds of thousands of people died. Though the authorities officially registered 242,000 fatalities, the real death toll is estimated at 650,000.   

One of the worst of a series of earthquakes to have struck East Asia in the 1920s also took place in China, the magnitude 7.8 Haiyuan earthquake of December 16, 1920. Landslides and ground fissures buried villages and caused rivers to change course. Some 200,000 people were killed. 

International relief aid 

These days, as is the case today in Syria and Turkey, international relief organizations are quick to mobilize when earthquakes occur. This also happened in 2010 when an earthquake struck Haiti at 16:53 local time on January 12. With a magnitude of 7, it was not the most powerful quake of the past century, but it was one of the worst in terms of its devastating impact.

Haiti, the poorest country in the western hemisphere, was ill-prepared for yet another natural disaster. In some regions, 90% of homes were destroyed. There are still no exact casualty figures, but international organizations estimate that the number of victims lies between 200,000 and 500,000.

This article was originally written in German.

Originally published on February 10, 2023, this article was updated and republished on September 9, 2023, following the deadly earthquake in Morocco.