The evening of January 21, 1725, in the Chita fortress was calm and quiet. By seven o'clock, it had long been dark, and people began to prepare for sleep. Suddenly, they heard loud rumbles and felt strange jolts that grew stronger. It seemed as if the earth would soon open up and everything would fall into the abyss. The German traveler Daniel Messerschmidt, who happened to stop there for the night, recalled: "I was afraid that my house, which was very old, would collapse, as the beams creaked, and everything hanging on the walls moved like a pendulum of a clock." The tremors lasted for about half an hour. This was one of the largest earthquakes in the history of Russia, known as the Great East Siberian Earthquake.

In the morning, a frightened Messerschmidt went outside and saw a terrible sight: cracks appeared several centimeters wide, and the ice on the Chita River, despite the frost, had broken up. The residents of the fortress thought that the disaster had only affected them, but later the traveler learned that on the same day, houses were nearly destroyed in the Nerchinsk, Yeravnensk, and Telembinsk fortresses. Tremors were felt even in the Irkutsk area. At that time, they did not know how to accurately measure the intensity of earthquakes, but according to modern data, at the epicenter, it reached 11 points out of a possible 12. Significant casualties were avoided because Eastern Siberia was sparsely populated at that time, and the residents were left only with fear.

However, the Great East Siberian Earthquake was not the last for these places. From 1725 to 1905, there were four more similar events here with intensities ranging from 10 to 12 points. According to modern scientists, seismic zoning in Russia shows that 15% of the country's territory is occupied by seismically hazardous zones with intensities of 9-11 points. The Baikal seismic zone is one of the most dangerous.