Active Seismic Zones

In certain areas of the Earth, strong underground tremors sometimes occur, a rumble is heard, and ground vibrations cover significant areas, sometimes the entire Earth—this is an earthquake. In its epicenter, strong changes occur: deep and long cracks appear on the surface, landslides are observed, buildings are destroyed, etc.

The earth shook
And cracked...
Deep
Cracks and pits formed.
The earth was covered with scars.

Every year, more than 10,000 noticeable earthquakes occur on our planet, but only about 150 of them are particularly destructive, catastrophic. In Kyrgyzstan, 600–700 earthquakes occur annually.

Active seismic zones are usually associated with orogenic and tectonic movements in the Earth's crust, and the movement of continental plates.

One of the most beautiful places in Kyrgyzstan—Lake Sary-Chelek—was formed as a result of an earthquake when part of a mountain collapsed, creating a blockage on the river Khoja-Ata.

In the plains, earthquakes are rare, and in most cases, people do not notice them.

The process of an earthquake is intermittent. The mountain mass, disrupted by a fault, moves slowly. During this time, tectonic stress accumulates along the fault. When it begins to exceed the strength of the rock's cohesion, the mass shifts sharply along the fault (almost instantaneously), releasing the accumulated potential energy. Seismic waves (longitudinal and transverse) spread in all directions. On the Earth's surface, they cause earthquakes. This process repeats at certain time intervals, which depend on the rate of accumulation of elastic deformations. The section of the surface of the fault, along which the seismogenic displacement of rocks occurred, is called the earthquake focus.

Tectonic movements manifest on the surface of the ground as shifts, uplifts or depressions, cracks, trenches, seismic ruptures, and landslides. For example, in Kemin, in 1911, as a result of a catastrophic earthquake (up to 11 points), deep intermittent cracks appeared on the surface, stretching for many tens of kilometers. Residual deformations on the surface in some places reached 3–4 meters. Horizontal displacements of the ground and large landslides were also observed. According to the unanimous testimony of all eyewitnesses, the underground shocks were vertical: yurts and houses made of peat and wooden logs, which are rarely found here, were thrown up quite strongly.

In the manuscript and publication department of the Academy of Sciences, a brief description of this earthquake was found from one of its eyewitnesses:

The earth was shaking,
Animals broke free from their ties...
The trembling mass
Seemed about to split open.
The mountains were collapsing...

The earth was trembling,
The animals were breaking free,
The trembling black earth
Was about to be destroyed.
The mountains split and stones fell.

It is possible that this earthquake was the reason for the widespread saying among the people, aptly expressing the general confusion and panic: "Who noticed whom? They say, Byrzhybay was buried under the rubble of a destroyed house."

In Kyrgyz oral folk creativity, there are vivid examples describing the consequences of earthquakes, for example, in the epic "Semetey":

The earth turned over,
The seas dried up and became plains,
The mountains sank, and lakes were formed.
If during an earthquake there is no significant ground movement, no elevations or depressions are formed, it means that the earthquake occurred at great depth. For instance, one of the earthquakes recorded in the Pamir Mountains occurred at a depth of 300 km. Seismological instruments have established that earthquakes in the Himalayan mountains occur at even greater depths. Such earthquakes are called ultra-deep. In Central Asia, the overwhelming majority of earthquakes occur at depths of 10–40 km.

It is known that as one goes deeper into the Earth, the temperature rises sharply. A borehole on the Kola Peninsula at a depth of 11,000 meters showed a temperature of 200°C. According to one of the hypotheses of scientists, about three billion years ago, the Earth was a huge molten sphere. Over time, this sphere cooled, decreased in volume, a crust formed, while a fairly high temperature remained at the center of the Earth. According to the hypothesis of Littleton, a professor at Cambridge University, the radius of the Earth has decreased by 300 kilometers compared to its original size. The Earth has constantly undergone and continues to undergo changes, which is reflected in Kyrgyz oral folk creativity:

In this land that is trembling,
Which part remained intact?!

Is there anything unchanging
On this vast Earth?!