Crustal strain in the rogoun dam area

Abstract In recent years much attention has been paid to the study of crustal movements within tectonically active regions. The present work is specially of interest since it deals with the site where one of the largest hydroelectric plants in the world is being built. The erection of the Rogoun HPP on the Vakhsh river involves the filling of a 320 m high dam using local materials and the construction of an underground-head hydroelectric unit with substations and auxiliary services. The work gives an evaluation of features and rates of seismotectonic deformations in two layers of the earth's crust (0.9 km and 10–25 km), obtained for a period of 28 years, within an area of 3 thousand km 2 around the HPP. These data allowed us to determine the complex block structure of the region. Based on instrumental data concerning strain processes occurring within the construction site, an evaluation is given of recent movements in the areas adjoining the Ionakhsh fault and the dislocations in its feather jointing.