Neotectonics from Geomorphic Indices: Highlights from Main Mantle Thrust (Pakistan).

The collision of the Eurasian and Indian plates has resulted in two spatially offset subduction zones, the Makran subduction zone to the south and the Himalayan convergent margin to the north. The Main Mantle Thrust (MMT) and adjoining regions have a complex geomorphic setting and geological variations with a number of active faults that were connected with numerous major devastating earthquakes in the investigation. Our study was carried out to develop a DEM based geomorphometric approach to study the stream power model and hypsometric analysis along the MMT and surroundings to achieve rigorous investigation of its potential to delineate active topography. Active tectonics in this region has greatly influenced the drainage system and geomorphic expressions. The study area is a junction of three important mountain ranges (Hindu Kush-Karakorum-Himalayas) and thus is an ideal natural laboratory to investigate the relative tectonic activity resulting from the India-Eurasia collision. Morphotectonic and geomorphometric evaluations of the MMT and surrounding regions were conducted by associating various DEM derived geomorphometric indices such as steepness (K_s), hypsometric integral (HI_s), Hack gradient index (SL) and concavity (θ). From the results obtained, we deduce that these combined procedures reveal the highly active deformed zones connected to neotectonics. Ground validations and Landsat satellite imagery also give clue about the active faults based on the offsetted channels, triangular facets and severely deformed topography. [ABSTRACT FROM AUTHOR]