Recent tectonics and seismicity of the western Altai-Sayan mountainous region, Junggar basin, and Chinese Tien Shan

Abstract

According to GPS monitoring, recent tectonic process between Tarim and West Siberia in the band within 80°–95° E is generated by the northward movement of the Tarim block. During the accompanying horizontal compression of the area, orogeny takes place within linear mobile zones when blocks are squeezed into the upper half-space. When the orientation of the mobile zones is transverse to the compression direction, the leading orogenic process is reverse faulting. When these directions intersect at an acute angle, the principal features of the mountain relief are formed by oblique-slip and strike-slip faults.The spatial distribution of seismic activity A10 over a 40-year period of instrumental observations within the mobile zones of the study area is extremely nonuniform. Seismic activity increases to the south, toward the source of deformations—the Indo-Eurasian collision. The maximum activity is observed at the reverse-fault boundaries of the eastern Tien Shan (~40). The seismic activity of the strike-slip fault boundaries of the Great Altai is considerably lower (0.11–0.16).