**3. Northwestern part of the Talas-Fergana fault**

36 Earthquake Research and Analysis – Seismology, Seismotectonic and Earthquake Geology


Fig. 2. Digital map of relief of the western Tian Shan. The locations of the investigated test

On the prospected ranges the TFF line usually goes across the slope of one of river valleys or a ridge (range) slope. Along the line there is usually a fault scarp in the form of a swell. Height of this scarp is usually equal to several dozens centimeters - the first meters. On the investigated ranges the numerous broken forms of a modern relief were found: valleys of temporary waterways and watersheds between them, upper parts of which are shifted in a horizontal direction - to the right to a distance from several dozens to several hundreds meters. The identical width and morphology of the shifted parts of dry valleys above and below the fault line testifies that the shift occurred quickly. It allows linking such shifts with

The majority of the shifted valleys of temporary waterways have remained below the fault line, where on the slope at earthquake a fault scarp was formed in the shape of a swell. This scarp has isolated the lower continuation of the broken valley, while seasonal waters found other drain, washing away the scarp in the lowest place. Further the isolated part of the

For definition of time of movements along the TFF indirect method of V.G. Trifonov (1985) was used. At formation of a scarp on the slope along the fault line a depression was also formed. This scarp has impound the waters flowing down the slope and filtering along the fault plane, which created conditions for swamping of the depressions in the vicinity of the

highway (Fig. 2).

sites are shown in the map.

earthquakes (Burtman et al., 1987).

valley could continue to be displaced along the fault.
