Faisal Shahzad

TecDEM: A MATLAB based toolbox for tectonic geomorphology, Part 1: Drainage network preprocessing and stream profile analysis

We present TecDEM, a software shell implemented in MATLAB that applies tectonic geomorphologic tasks to digital elevation models (DEMs). The first part of this paper series describes drainage partitioning schemes and stream profile analysis. The graphical user interface of TecDEM provides several options: determining flow directions, stream vectorization, watershed delineation, Strahler order labeling, stream profile generation, knickpoints selection, Concavity, Steepness and Hack indices calculations. The knickpoints along selected streams as well as stream profile analysis, and Hack index per stream profile are computed using a semi-automatic method. TecDEM was used to extract and investigate the stream profiles in the Kaghan Valley (Northern Pakistan). Our interpretations of the TecDEM results correlate well with previous tectonic evolution models for this region. TecDEM is designed to assist geoscientists in applying complex tectonic geomorphology tasks to global DEM data.

TecDEM: A MATLAB based toolbox for tectonic geomorphology, Part 2: Surface dynamics and basin analysis

We present the analytical capability of TecDEM, a MATLAB toolbox used in conjunction with Global DEMs for the extraction of tectonic geomorphologic information. TecDEM includes a suite of algorithms to analyze topography, extracted drainage networks and sub-basins. The aim of part 2 of this paper series is the generation of morphometric maps for surface dynamics and basin analysis. TecDEM therefore allows the extraction of parameters such as isobase, incision, drainage density and surface roughness maps. We also provide tools for basin asymmetry and hypsometric analysis. These are efficient graphical user interfaces (GUIs) for mapping drainage deviation from basin mid-line and basin hypsometry. A morphotectonic interpretation of the Kaghan Valley (Northern Pakistan) is performed with TecDEM and the findings indicate a high correlation between surface dynamics and basin analysis parameters with neotectonic features in the study area.

Stream Profile and Neotectonic Analysis in Hazara Kashmir Syntaxis using Shuttle Radar Digital Elevation Data

Digital elevation models are replacing traditional topographic maps in geosciences with the advent of space technology. We used digital elevation models from SRTM data for neotectonic and stream profile analysis in Hazara Kashmir Syntaxis. Hazara Kashmir Syntaxis is a NNW-SSE complex tectonic zone and makes a hair pin like structure located in North Western Himalayan Fold and Thrust Belt. There is no distinct pattern of Hazara Kashmir Syntaxis and surrounding faults i.e. Main Boundary thrust, Main Central Thrust, etc. which marks loop around it. NW-SE trending Himalayan Frontal thrust starts from the core of the Syntaxis while other faults like Kotil thrust, Riasi thrust and Tanda fault runs along NS directed Jehlum Strike Slip Fault. Seismicity is distributed along all the parts of the Syntaxis i.e. in the core and along the outer loop but decreases southward. Major earthquakes like Kangra (1905) and Muzaffarabad Earthquake (2005) caused surface deformation in the area and gave motivation for this study. Streams network has been extracted from DEM; Choice of stream delineation algorithms can influence the stream parameters like contributing area, slope, elevation, downstream distance and Strahler order. This study focuses Kunhar River, Kishanganga Rivers and their tributaries. Both rivers and their tributaries come across many faults in this area at different locations which help us in understanding the tectonic activity in this region. We use stream power law to calculate steepness and concavity indices by making area slop plots. Tectonic and seismicity map also supports that the area is tectonically active showing thrust faulting. The results show high uplift eastern and western flanks of the Syntaxis and also along the loop while in the core it is comparatively less uplifted.

Remote Sensing Analysis of Recent Active Tectonics in Pamir Using Digital Elevation Model: River Profile Approach

Digital elevation models (DEMs) are key component for computer-based analyses of river profiles, drainage basin as it provides elevation information for the land surface throughout the catchment of the area. During the Cenozoic uplift of Tibetan plateau and surrounding ranges due to India-Eurasia collision, the tectonic processes are interacting with the local random effects (e.g. Landslides, Glaciations and climatic Changes) and are linked with the development of a unique river network in this region. These rivers have distinct patterns and are controlled by different tectonic and climatic regions. Drainage history of the Pamir is related to continental movements of the plates, displacements of the tectonics, regional uplift and erosion of various individual tectonic units. This study focuses on the application of remote sensing techniques in order to show the spatial variation of uplift and deformation along the right bank tributaries of Pyanj (Vanch, Yazgulem, Aksu-Murghab-Bartang, Gunt-Alichur and Shokhdara) and one of the few left bank tributary (Shiveh river) and Pyanj itself. DEM data is used to extract river network in this area. Moreover, slopes and drainage areas are also calculated from Digital Elevation Model. Based on the stream power law, we make area-slope plot so as to derive channel parameters like concavity (thetas) and steepness (Ks) which are related closely to uplift and deformation. The lineaments and major tectonic features have been digitized from geological maps of the region. The uplift, steepness and hack index maps have been generated by using some specially designed algorithms for this purpose.

Drainage network and seismological analysis of active tectonics in Nanga Parbat Haramosh Massif, Pakistan

The Nanga Parbat Haramosh Massif (NPHM) is an active tectonic feature of the north-western Himalayas. The recent seismic activity lies on an active seismic zone between Sassi and Raikot, from north to south, and is called Raikot-Sassi fault zone. The drainage pattern of NPHM is disconnected at different location especially along the active Raikot-Sassi fault zone. The stream profile analysis of Indus River in the massif revealed four different locations of the active faults. The spatial distribution of geomorphic indices suggests that the western portion of the massif is more deformed compared to any other location. We observed variable relative uplift rates ranging from 7–13 mm yr−1 in different locations with higher rates in the area along Raikot fault. The focal mechanism solutions (FMS) of recent events suggests that these active faults are strike slip with major thrust components. The correlation dimension values suggests that the events have failed to fill up the plane in the source zone. The heterogeneous drainage pattern, stream profile analysis and seismological characteristics suggest that the Raikot Fault zone is highly deformed and relates to strike slip dominated thrusting.

Remote sensing analysis of quaternary deformation using river networks in Hindukush region

The Hindukush region in north-western Pakistan is amongst the most active geomorphic regions in the world and is bounded by principal active zones. This study focuses on the application of remote sensing techniques in order to show the spatial variation of uplift and deformation along the Tirch Mir Massif and Shyok suture zone in the eastern Hindukush. Stream profile analysis and box counting techniques were employed on drainage network extracted from digital elevation model (DEM) to calculate the geomorphic indices and fractal dimension. The estimation of fractal dimensions allows us to measure the degree of complexity by evaluating how the dimension measurement increases or decreases at different scales with respect to the vulnerability of the surface deformation (surface roughness). The objective is to quantify the influence of neotectonic activity on the drainage system by measuring the reduction in complexity as the deformation intensity increases. We used a steepness index map to prepare a relative uplift rate map of the area. It is also observed that the main control over the drainage system is tectonic uplift. Quaternary faults in the region control local drainages and the deflection of rivers and stream offsets is a further evidence of neotectonic activity. This study can be improved by using high resolution imagery and GPS data. The anomalous and heterogeneous behaviour of drainage pattern, seismicity and fractal dimension values also prove the active nature of the Hindukush region.

Remote sensing analysis of ongoing deformation in Hazara Kashmir Syntaxis in Northern Pakistan

Hazara Kashmir Syntaxis (HKS) is a complex tec-tonic feature in North Western Himalayan Fold and Thrust Belt. Himalayan Frontal thrust starts from the core of the Syntaxis while other faults like Kotil thrust, Riasi thrust and Tanda fault runs along NS directed Jehlum Fault. Seismicity is distributed along all the parts of the Syntaxis i.e. in the core and along the outer loop but decreases southward. The Kangra (1905) and Kashmir Earthquake (2005) are major outputs of the ongoing deformation process and thus gave motivation for this study. This study focuses Kunhar, Kishanganga, Jehlum and Poonch River and their automatically extracted tributaries. The drainage pattern of these rivers is controlled by different tectonic and climatologically changes in the region. Digital elevation models (DEMs) are used for drainage network extraction as it provides elevation information for the land surface throughout the catchment of the area. Drainage network has been extracted from Shuttle radar digital elevation data (SRTM-DEM). Rivers are sensitive to changes in tectonic deformation, adjusting over different periods of time depending on the physical properties of the host rocks, climatic effects and tectonic activity. Thus, the drainage system of a region records the evolution of tectonic deformation. The stream profile analysis of these four rivers provides information about absolute uplift condition in the region. This analysis provides us with different indices and they can later provide us several maps which, integrated in a GIS, allows a better interpretation of the results. We apply fractal analysis to these four rivers and try to study the rigidity of the areas from where they are passing. This is later confirmed with the steepness and concavity indices of the areas to identify the spatial distribution of the different rock types. We can separate various tectonic units and their deformation using knickpoints, concavity and steepness indices and their fractal behavior.

Understanding neotectonic induced surface deformation from drainage network using digital elevation models

Digital elevation models (DEMs) provide an opportunity to quantify surface deformation in terms of elevation and its derivatives. Darvaz strike-slip fault is a junction zone of the Tajik depression and the Northern Pamirs. The Pyanj River makes a right angle turn after crossing the Central Badakhshan and Henjvan fault system and runs parallel to the Darvaz fault to the southwest on leaving the Pamir to join the Amu River 300 Km southwest. The river profile analysis in this region using SRTM digital elevation model gives information about the tectonic influence on the local drainage network. We create area-slope plot in order to derive channel parameters like concavity and steepness indices that are related closely to surface uplift and deformation. The results show that the Kyzylsu-Surkhab-Vakhsh river system is disrupted by faulting in its middle and lower reaches where they finally join the Pyanj-Amu river system. It is also observed that the main control over the drainage system is tectonic uplift due to ongoing complex faulting because of frequents earthquakes in this region. The quaternary faults in the region control local drainages and the deflection of rivers and stream channels is a further evidence of the recent fault activity. This study can be improved by using high resolution imagery and GPS data.