An earthquake is considered one of the most formidable natural phenomena that bring terrible disasters to man.
Catastrophic earthquakes are rare — once a year on average; strong earthquakes (not catastrophic) are observed annually up to ten; destructive aftershocks - up to a hundred; shocks causing damage to stone buildings - up to a thousand; shocks that do not cause damage - up to ten thousand, and weak shocks, recorded by special devices - up to one hundred thousand per year.
Japan accounts for a quarter of all earthquakes in the world. In 1959, Japan recorded 930 earthquakes, but it was a "quiet year." In 1930, the number of earthquakes reached 5, 744!
In Tajikistan, seismographs record up to a thousand earthquakes annually.
The duration of each shock during an earthquake is calculated in seconds. But sometimes tremors continue with some interruptions for many days, months and even years. So, the earthquake in Alma-Ata, which began on May 28, 1887, lasted about three years, and during this time several hundred tremors were observed