Abstract
Using E-W and vertical deformation-rate maps derived from radar
interferometric time-series, we analyze the deformation field of an
entire orogenic segment, i.e., the Tajik depression and its adjoining
mountain belts, Tian Shan, Pamir, and Hindu Kush. The data-base consists
of 900+ radar scenes acquired over 2.0–4.5 years and global navigation
satellite system measurements. The recent, supra-regional kinematics is
visualized in an unprecedented spatio-temporal resolution. We confirm
the westward collapse of the Pamir-Plateau crust, inverting the Tajik
basin into a fold-thrust belt with shortening rates decaying westward
from ~15 to 2 mm/yr. Vertical rates in the Hindu Kush
likely record slab-dynamic effects, i.e., the progressive break-off of
the Hindu Kush slab. At least 10 mm/yr of each, uplift and westward
motion occur along the western edge of the Pamir Plateau, outlining the
crustal-scale ramp along which the Pamir Plateau overrides the Tajik
depression. The latter shows a combination of basin-scale tectonics,
halokinesis, and seasonal/weather-driven near-surface effects. Abrupt
~6 mm/yr horizontal-rate changes occur across the
kinematically-linked dextral Ilyak strike-slip fault, bounding the Tajik
fold-thrust belt to the north, and the Babatag backthrust, the major
thrust of the fold-thrust belt, located far west in the belt. The sharp
rate decay across the Ilyak fault indicates a locking depth of ≤1 km.
The Hoja Mumin salt fountain is spreading laterally at ≤350 mm/yr. On
the first-order, the modern 20–5 and fossil (since ~12
Ma) 12–8 mm/yr shortening rates across the fold-thrust belt correspond.