Mass Movements Along the Karakoram Highway with a Focus on Seismically Induced Mass Movements
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Mass Movements along the Karakoram Highway with a focus on Seismically Induced Mass Movements From the Faculty of Georesources and Materials Engineering of the RWTH Aachen University Submitted by Sajid Ali M.Sc. from Okara, Pakistan in respect of the academic degree of Doctor of Natural Sciences approved thesis Advisors: Univ.-Prof. Dr.rer. nat. Klaus Reicherter Univ.-Prof. Dr.rer. nat. Florian Amann Date of the oral examination: 12.05.2020 This thesis is available in electronic format on the university library’s website Eidesstattliche Erklärung Hiermit versichere ich eidesstattlich, dass ich die Dissertation selbstständig verfasst und alle in Anspruch genommenen Hilfen in der Dissertation angegeben habe. Unterschrift Ort, Datum This work is dedicated to my loving father “Sikander Ali (1949-2007)”, who is a source of motivation and inspiration for me and many others! Acknowledgments Firstly, I would like to thank my supervisor, Prof. Dr. Klaus Reicherter for continuous support, inspiration, motivation, advices and answering a lot of my questions, specially “the last question”. I am obliged to Dr. Muhammad Basharat (University of Azad Jammu and Kashmir, Muzaffarabad, Pakistan) for his guidance during field campaign and suggestions. Scientific and technical support from Prof. Dr. Florian Amann and Dr. Anja Dufresne (Chair of Engineering Geology and Hydrogeology) was essential for successful completion of the work. I am also indebted to: Higher Education Commission (HEC) of Pakistan and Deutscher Akademischer Austauschdienst (DAAD) for their support. Pakistan Meteorological Department for provision of weather data. Lt. Gen. Muhammad Afzal and Maj. Gen. Inam Haider Malik (Frontier Works Organization, Rawalpindi, Pakistan) for provision of accommodation and transportation during field work along the Highway. Maj. Hassnain Farooq and Maj. Rameez Ali for organizational support during field work. Mr. Peter Biermanns for valuable comments and suggestions for writing process. To anonymous referees and Editor Paolo Tarolli (University of Padova, Legnaro, Italy) for valuable comments. Mr. Rashid Haider for giving access to relevant publication in Geological Survey of Pakistan’s library and assistance during field work. My NUGGED family for refreshing coffee and lunch breaks, Ms. Evelyn Bützler and Dr. Tabea Schröder for answering many questions, Mr. Christopher Weismüller for drone trainings, Mr. Wahid Abbas and Mr. Aram Fathian Baneh for comments and Ms. Jorien van der Wal for fruitful seminars. I am grateful to my family specially my mother “Ameeran Bibi” for her continuous care, support and prayers, my son “Hussain Ali” for making my life colorful, my wife Sumaira for scarifying her weekends with unlimited support (24/7) and patience during busy routines, my brother “Abid Ali” for doing everything for me far from Pakistan. Abstract Landslide and its severe impact on infrastructure is talk of the town now a days. It is a complex process, which is quite difficult to understand and predict. Multiple remote sensing and site specific approaches have been employed to determine associated hazard and risk. “Regional to site specific approach” was applied in this study. Initially, regional landslide susceptibility map was prepared by using geographic information system. Potential hazardous sites identified during this stage were further investigated in detail. This study is concerned about the Karakoram Highway (KKH), located in north Pakistan. It is an important part of the China Pakistan Economic Corridor (CPEC), connecting Arabian Sea with southwest China. It is also considered a lifeline of the Gilgit-Baltistan, being only all-weather physical connection with rest of country. It passes through plateau, high plains and deeply incised gorges (~6500 m). From Thakot onwards, it runs along four rivers: Indus, Gilgit, Hunza and Khunjerab. It is situated at the junction of two plate boundaries: India and Eurasian plate. Ongoing collision between these two plates has produced different tectonic environments and seismic zones. Region has witnessed major historical and recent earthquakes e.g. Pattan 1974 (M=6.2), Astore 2002 (M=6.3) and Kashmir Earthquake (M=7.6), which completely damaged some segments of the Highway. Landslide inventory map (LIM) was basic requirement of the entire process to prepare hazard and risk maps of the Highway. Previously published reports, articles, books and road clearance logs were consulted to prepare multi-temporal inventory. Furthermore, multi-temporal satellite imagery was examined to locate active and potential slope failures, which were further classified into size and failure mode categories. Extent and type of slope failures was then validated during multiple field campaigns. Subsequently, geological map was prepared by digitizing existing published maps. Additionally, influence of lithological units (formation/group) and individual lithologies on spatial distribution and types of landslides was analysed. Highly fragmented ultramafics, deeply weathered plutons and mechanically shattered schists and slates have high landslides density. Furthermore, degree of fragmentation and attitude of joint sets defined mode of slope failure. The Highway passes through two climatic zones: Monsoon and semi-arid to arid zone. Former is characterized by torrential rainfalls whereas latter has low mean annual rainfall (>250 mm). Strong correlation between rainfall intensity and mass movements has been found. Besides, variations in temperature coupled with precipitation initiated rockfalls. Moreover, active faults (MBT, MMT, KSF, RF, MKT, and KF) and shear zone (KJS) characterize the KKH. Rock mass is highly jointed and sheared close to these structure. Landslide clusters were found close to these structure indicating their strong control. Preparation of landslide susceptibility map (LSM) involved analytical hierarchy process (AHP) based semi-quantitative technique. Ten parameters (lithology, seismicity, rainfall intensity, faults, elevation, slope angle, aspect, curvature, land cover and hydrology) were used to assess susceptibility. Spatial analysis was performed to estimate effect of these parameters over landslide distribution. Each parameter was rated by using expert based AHP. Weighted overlay technique was employed to produce final map, which was further classified into four levels: low, intermediate, high and very high susceptibility. High and very high susceptibility areas were found close to active faults. Three case studies (Jijal sub-section, Raikot Bridge sub-section and Attabad sub-section) were discussed to explain the final map. To end with, Landslide density analysis (LDA) and receiver operative curve (ROC) determined accuracy of the map as 72%, which was considered reasonable for planning and mitigation. High and very high susceptibility characterize long segment of the Besham-Chilas section, therefore was preferred for risk assessment. LIM, slope angle distribution (SAD) and satellite imagery analysis were utilized to locate rockfall and debris flow sources. Which were further exploited to assess runout by using open source and customizable software “FLOW-R”. Sites with maximum probability to reach and damage the Highway, were empirically rated for risk assessment. Modified Pierson’s Rockfall Hazard Rating System (MRHRS) rated potential rockfalls whereas semi-quantitative criteria was employed to rate debris flows. Lastly, final map was then classified into four risk levels: low, intermediate, high and very high. Immediate application of countermeasures for segments at high and very high risk were proposed. This study encompasses important dimensions of mass movements along the Highway. But still, some other aspects like numerical and physical modeling needs to be done for understanding and evaluation of the entire process. Kurzfassung Bergrutsche und ihre schwerwiegenden Folgen, vor allem in Bezug auf die Zerstörung verschiedenster Infrastruktur, sind heutzutage von breitem öffentlichen Interesse. Hinter diesen Ereignissen stecken komplexe Prozesse, die schwer vorherzusagen sind. Diese Arbeit zeigt Ansätze auf, um regional und standortspezifisch mit verschiedenen Methoden, u.a. der Fernerkundung, die potentielle von Bergrutschen ausgehende Gefahr zu bewerten. Eine GIS- basierte Analyse der regionalen Anfälligkeit für Bergrutsche dient dabei als Grundlage für nachfolgende detaillierte Vor-Ort-Untersuchungen. Gegenstand der Studie ist der Karakoram-Highway (KKH) im nördlichen Pakistan, der einen bedeutenden Bestandteil des Wirtschaftskorridors zwischen China und Pakistan („China Pakistan Economic Corridor“, CPEC) darstellt. Dieser verbindet das Arabische Meer mit dem Südwesten Chinas. Neben der wirtschaftlichen Bedeutung stellt der KKH auch die „Lebensader“ der pakistanischen Region Gilgit-Baltistan dar, deren einzige Verbindung zum Rest des Landes er ist. Der KKH führt durch (Hoch-) Ebenen und tiefe (~6500 m) Schluchten. Von der Stadt Thakot aus folgt der Highway in nördlicher Richtung vier verschiedenen Flüssen (Indus, Gilgit, Hunza und Khunjerab) und verläuft entlang der Indisch-Eurasischen Plattengrenze. Die andauernde Kollision dieser beiden Kontinentalplatten bedingt im Untersuchungsgebiet verschiedene seismische Zonen mit unterschiedlichen tektonischen Konfigurationen. Die Region war Schauplatz bedeutender historischer- und rezenter Erdbeben, wie z.B. Pattan 1974 (M=6.2), Astore 2002 (M=6.3) und Kashmir 2005 (M=7.6), die Teile des KKH jeweils komplett zerstörten. Eine Kartierung des gesamten