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Abstract
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The Zagros Fold-Thrust Belt is a tectonically active region within the Alpine-
Himalayan orogenic system resulting from ongoing convergence between Afro-
Arabian and Central Iranian plates. The presence of various geomorphic features in
this region provides an ideal natural case for identifying deformed landforms
resulting from active tectonics. The relative tectonic activity along the Lar and
Didehban faults within the Zagros Fold-Thrust Belt, SW Iran was evaluated using six
DEM-derived geomorphic indices: the stream-gradient index (SL), drainage basin
asymmetry (AF), hypsometric integral (HI), valley floor width-valley height ratio (Vf),
drainage basin shape (Bs), and mountain-front sinuosity (Smf). These indices were
combined to yield the relative active tectonics index (Iat) that allows the variation of
tectonic activity along the Lar and Didehban faults to be related to variations in rates
of incision, tectonic tilting and uplift. This variable tectonic activity was characterized
by different Iat values along the faults. The low to high relative tectonic activity (class
1: 1 < Iat < 1.5, class 2: 1.5 < Iat < 2, class 3: 2 < Iat < 2.5, class 4: 2.5 < Iat) correlates
with variable geomorphic features along the faults. The results of this study present
an approach for assessing the effects of active tectonics and also for sustainable land
use planning over a large area.
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