Earthquakes and Tsunami

Updated February 21, 2017 | Factmonster Staff

An earthquake is a trembling movement of the earth's crust. These tremors are generally caused by shifts of the plates that make up the earth's surface. The movements cause vibrations to pass through and around the earth in wave form, just as ripples are generated when a pebble is dropped into water. Volcanic eruptions, rockfalls, landslides, and explosions can also cause a quake.

A tsunami (pronounced soo-NAHM-ee) is a series of huge waves that occur as the result of a violent underwater disturbance, such as an earthquake or volcanic eruption. They are sometimes mistakenly referred to as tidal waves, but tsunamis have nothing to do with the tides.

  • Where: China
  • When: 1556
  • More than 830,000 people in the Shensi Province were killed by this earthquake. It caused the collapse of caves that people had carved out of cliffs and used for homes.
  • Where: Prince William Sound, Alaska
  • When: 1964
  • The strongest earthquake in North America, 9.2 magnitude, was followed by a seismic wave 50 ft high..
  • Where: Armenia
  • When: 1988
  • Nearly 4,000 square miles of densely populated land was ravaged by an earthquake. Three cities were leveled, killing more than 25,000 people. Other countries were able to send the Armenians supplies and rescue workers. Miraculously, 15,000 people were recovered from the rubble.
  • Where: Papua New Guinea
  • When: 1998
  • A tsunami wiped out many villages in the island nation. More than 2,000 people were killed and many more were left homeless.
  • Where: Sumatra, Indonesia
  • When: 2004
  • A 9.0 earthquake triggered a tsunami in the Indian Ocean, that killed more than 226,000 in 12 countries and left millions homeless, making it the deadliest tsunami in world history.
  • Where: China
  • When: 2008
  • A 7.9 earthquake killed over 40,000 people and injured thousands more in the Sichuan, Gansu, and Yunnan Provinces in western China. Nearly 900 students were trapped when Juyuan Middle School in the Sichuan Province collapsed from the quake.

For a list of recent earthquakes and largest earthquakes, see Earthquakes.

For a list of earthquakes, see Earthquakes and Volcanic Eruptions at

For more information about earthquakes, see The Severity of an Earthquake and Number of Earthquakes Worldwide at

For other tidal waves, and tsunami, see Floods, Avalanches, and Tidal Waves at

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