Seismicity of Russia and the Former Soviet Union

Tien Seismicity Map and Composite Regional Catalog

(39-48 N, 76-87 E)

The mountainous region of the Tien Shan is one of high seismicity. Historical earthquakes are concentrated in three areas: in the northern Tien Shan; along a narrow belt in the southern Tien Shan; and along the Talas-Fergana fault zone. Between 1885 to 1992, as many as 25 large earthquakes with magnitudes greater than 6 occurred in the northern Tien Shan. Twelve of these earthquakes had magnitudes equal or larger than 7. The last large earthquake occurred in 1992 (at Rochnor-Ata, 15 May 1992, M=6.2).

The principal damage from these earthquakes resulted from triggered landslides. Many landslides are known from historical records, some with catastrophic effects. The most recent examples are the landslides near the village of Maily-Su (connected with the Rochnor-Ata earthquake). In 1885, a strong earthquake occurred near Bishkek, triggering several landslides. The largest of these had a thickness of 20-30 meters, a width of 500 meters and a length of about 2 km. The 1911 earthquake known as Kemin triggered snow-ice avalanches and several landslides, and the Chatkal earthquake of 1946 resulted in a landslide with a length of 1 km, 100 meters wide and displaced a volume of rocks of 15 million cubic meters.

In the area of Lake Issyk-Kul, almost all epicenters of strong earthquakes are located to the north of the basin, within a narrow zone extending east-west between the latitudes 75 and 79 degrees North. The most important of these earthquakes are Vernensk (M>6.5, 1887), Chilik (M>7.5, 1889), Kemin (M>8, 1911), Sarykamish (M=6.5, 1970), and Djialanash-Tiup (M=6.5, 1978).