Earthquakes, such as the one which hit the Soviet Republic of Tadzhikistan, have killed thousands of people around the world in the past 20 years.

But the most lethal earthquake in recorded history hit Shaanxi in China in 1556, killing 830,000 people.In 1920 a quake in China's Jiangsu province killed 180,000, and on July 28, 1976, China suffered the worst quake in its modern history.

Some 240,000 died when the northeastern city of Tangshan was almost completely leveled by a quake measuring 7.8 on the open-ended Richter scale.