Studies of some exogenous processes at a mountain area of Tadzhikistan using aerial photogrammetric technique

Abstract

Stereophotogrammetric processing of aerial photographs taken at different times has been used for quantitative studies of gullies dynamics at a seismic mountain area of Tadzhikistan. The study's objects were two gullies of 4-10⁵ sq. m area and to 150 m depth, having common fan. For 20 years mean thickness of layer washed from the gully slopes appeared to be 7±1 m, the gullies area increased for 65000 sq. m. Irregularity in the denudation rate through time has been established; for two years of study including an anomalous meteorological period the values were 4±1 m and 20000 sq. m respectively. The analysis of the stereophotogrammetric measurements accuracy (using surface stereo-photogrammetry) has revealed that the-aerial photographs scale 1:10 000-1:20000 can be effectively used for estimation of gully erosion within tectonic active mountain region.