The surface is never alone. Every hour on the planet is about 10 earthquakes. Catastrophic earthquakes occur on average once a year. Strong earthquakes each year is about 10. Devastating tremors up to 100. Shock, causing damage to stone buildings, up to 1 thousand. Shake that do not cause damage, up to 10 thousand. Weak aftershocks recorded up to 100 thousand a year.
The duration of each stimulus during an earthquake is calculated in seconds. Sometimes the shocks are long. They can be continued, with some interruptions, for many days, months and even years. For example, the earthquake in Alma-ATA, which began on may 28, 1887, lasted about three years. During this time there was several hundred aftershocks.
The earthquake, which claimed the greatest number of human lives, occurred in the Chinese province of Shanxi. At the time he was killed 830 thousand people.
The area where the most earthquakes are frequent, cover the planet in two belts. The first zone extends from the Sunda Islands to Panama isthmus. He goes through the Himalayas, the mountains of the Pamir-Alai mountains, the Caucasus, the Balkans, the Apennines, the Pyrenees, and then across the Atlantic to Mexico and Central America.
The second zone is Pacific. He goes through Japan, the Philippines, Hawaii, the Kuril Islands, Alaska. Then continues along the Western shores of the American continent through the mountains of California, Peru, Chile and next to Tierra del Fuego and Antarctica.