Syed Amer Mahmood

Analyzing Spatial Autocorrelation for the Hypsometric Integral to Discriminate Neotectonics and Lithologies Using DEMs and GIS

This investigation documents the sensitivity of the hypsometric integral (HI) and its relationship to neotectonics and lithology. We used digital elevation models (DEMs) of 30 and 90 m spatial resolution from the Shuttle Radar Topographic Mission (SRTM) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) to calculate HI values in the Hindu Kush and its vicinity (Northwest Pakistan and Northeast Afghanistan). We used an analysis grid of regular squares of different sizes to calculate maximum, minimum, and mean elevations. The spatial distributions of HI do not show clear spatial patterns and correlation with mean elevation or relief amplitude. We applied spatial pattern analysis using Local Indices of Spatial Autocorrelation (LISA) to measure the degree to which our HI distribution was clustered, dispersed, or randomized. LISA analysis shows that the data are autocorrelated because of high positive z-scores. Hot spots (clusters with high HI values) are consistent with tectonic uplift and show a strong correlation with the different structural domains in the region. Cold spots represent recent sedimentation close to faults and coincide with shallow earthquake clusters in the region. The HI values do not show any correlation with relative topographic position or lithology. Analysis of HI distribution shows that they are robust and independent of digital elevation model (DEM) resolution but are strongly scale dependent. The LISA technique allows the extraction of clusters of the HI that reveal recent tectonic processes; otherwise it is difficult to interpret the high variability of HI values. The scale dependency of the HI may reflect the varying importance of drainage network and hillslope processes.

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.

Variation in Meteorological Parameters Over Pakistan during April 2014

In this study we investigated the meteorological data comprising temperature, dew point, humidity and mean sea level for four major cities of Pakistan (Karachi, Multan, Lahore and Peshawar) on varying latitudes from 25°N to 34°N. These cities are selected to study the variation of coastal, southern, central and northern parts of Pakistan and different variations are observed in ranges i.e difference between lowest and highest values. A clear variation in ranges of meteorological parameters are investigated for these cities to validate this research. This variation in meteorological parameters is because of climate change due to flow of high moisture laden winds from Arabian sea towards Karachi coast in the south. The results obtained regarding dew point temperature, moisture content and atmospheric pressure in the southern city of Karachi represent low values instead of high. As a result, Karachi has different climatic patterns as a coastal city than other areas which are continental in climatic effects.

Comparative study of performance of real-time satellite-derived rainfall in Swat Catchment

Most of the conventional models require rainfall data for realistic modeling results, and where ground data is scarce, remotely sensed data plays a vital role. For monitoring, hydrological models require near real-time observations to allow for effective planning and forecasting. However, monitoring rainfall in mountainous region is difficult because of inaccessibility and sparse gauge density. However, the accurateness of these satellite estimates over different spatial and temporal scales is unknown. The study intended at carrying out a comparative analysis of satellite rainfall estimates as a substitution for ground-based rainfall observations in the Swat Catchment. Limited availability of temporally continuous available data records in Pakistan has been a problem and has effected the reliability of modeling results. As well as, data is not freely available and cost is the biggest hindrance to its usage. So, remotely sensed data plays a vital role both in terms of timely availability and its free of charge. For this region, only two remotely sensed gridded data products are freely available, i.e., NOAA RFE CA and TRMM RT. Respective two products have been analyzed by various verification statistics. RFE CA proves better probability of detection, false alarm ratio, threat score, and equitable threat score than TRMM RT. The outcome of this comparative study concludes that for hydrological modeling purposes, RFE CA data is the best choice in this region. The annual bias for RFE CA and TRMM RT is 14% (over-estimation) and 18% (under-estimation) over the years having coefficient of determination with the ground-based data of 0.87 and 0.76, respectively, on annual basis. The result shows the suitability of RFE CA for effective monthly rainfall-runoff modeling in Swat Catchment, Khyber Pakhtunkhawa, Pakistan.

Monitoring landscape response to tectonic forcings in Central Badakhshan-Hindukush-Pamir region using remote sensing data

This study deals with the remote sensing analysis of landscape response to tectonic forcings and its implications to understand the regional uplift conditions along the Shiveh River and Shiveh Lake in Central Badakhshan-Hindukush-Pamir region. Quantitative remote and field assessments of process-based laws are needed to accurately describe landscape uplift and denudation with respect to tectonics and climate.We evaluate and calibrate stream power bedrock-incision model under steady state conditions by studying stream profiles in a tectonically active Central Badakhshan region. Previous work in Pyanj region along Tajikistan-Afghanistan boarder and along Yarkun-Chitral region provides spatial and temporal control on rock-uplift rates. SRTM Digital elevation models (DEMs) are used to estimate differences in landscape morphology associated with along-strike northwest to southeast changes in tectonic and climatic conditions. Data is acquired in different stages; first, River longitudinal profiles, stream wise distance, elevation, and drainage area are generated from DEMs. Second, power-law regressions of channel slope as a function of drainage area are used to derive channel concavity and steepness indices. Slope-area data can be generated in a variety of ways, and several methods have been critically evaluated. An uplift rate map of the area has been prepared for further analysis of the drainage network. Siesmotectonic map of the area is also prepared by using seismological data compiled from various resources. The seismicity in this region shows a distinct pattern. Moment tensor solutions show strike-slip components with thrust dominance. The stream profile data can be used to delineate breaks in scaling that are related with the tectonic boundaries. Analysis of stream profiles supports the hypothesis that the study-area channels are in equilibrium with current uplift and climatic conditions. Channel steepness correlates with uplift rate. The uplift rate map shows variable differential uplift rates in this region and it is due to the ongoing complex faulting processes due to India-Eurasia collision. The quaternary faults in the region control local drainage and the deflection of rivers and stream channels is a further evidence of the recent fault activity. Mapping of some quaternary faults on Landsat data also confirms the change in style of deformation in this 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.