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Active deformation and relief evolution in the western Lurestan region of the Zagros mountain belt: new insights from tectonic geomorphology analysis and finite element modeling
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  • Matteo Basilici,
  • Alessandra Ascione,
  • Antonella Megna,
  • Stefano Santini,
  • Stefano tavani,
  • Ettore Valente,
  • Stefano Mazzoli
Matteo Basilici
Università di Urbino Carlo Bo
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Alessandra Ascione
University of Naples
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Antonella Megna
Instituto Nazionale di Geofisica e Vulcanologia
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Stefano Santini
Università di Urbino Carlo Bo
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Stefano tavani
Università degli Studi di Napoli Federico II
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Ettore Valente
Università degli Studi di Napoli Federico II
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Stefano Mazzoli
University of Camerino

Corresponding Author:[email protected]

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Abstract

2-D finite element modeling of both coseismic and interseismic deformation was performed along a transect across the seismogenic fault of the Mw=7.3, November 2017 Lurestan earthquake (Zagros Mountains). In order to extract information on the time-space distribution of uplift along the same transect, an investigation of the large-scale features of topography and river network was also carried out. Constraints from the spatial distribution of mean elevation, local relief and normalized channel steepness index (ksn), combined with those from river longitudinal profiles and transformed river profiles (chi-plots), were integrated with the results of geomorphological analyses aimed at the reconstruction of the development of the fluvial network. Despite the much longer timescale over which topography grows and/or rivers respond to tectonic or climatic perturbations with respect to even multiple seismic cycles, the outputs of the finite element model yield fundamental information on the source of the late part of the spatiotemporal evolution of surface uplift recorded by the geomorphological signature. Model outputs shed new light into the processes controlling relief evolution in an actively growing mountain belt underlain by a major blind thrust. They point out how co-seismic slip controls localized uplift of a prominent topographic feature ­– defining the Mountain Front Flexure – located above the main upper crustal ramp of the principal basement thrust fault of the region, while continuous displacement along the deeper, aseismic portion of the same basement fault controls generalized uplift of the whole crustal block located further to the NE, in the interior of the orogen.
Dec 2020Published in Tectonics volume 39 issue 12. 10.1029/2020TC006402