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The coastal cities and areas of Gwadar and Pasni in Pakistan, being highly vulnerable to tsunamis, are investigated for inundation and risk analysis. For modelling, both dynamic and static approaches are used for better understanding and for their comparative analysis. The tsunami wave potential in the Arabian Sea is estimated by compiling and assessing the palaeo-morphodynamics of tsunamite record discovered so far along its coastlines. The dynamic model is calibrated and validated with the inundation limits of the 1945 tsunami in the Pasni area. Further, for risk estimation, three different wave scenarios (7 m, 10 m, and 15 m) are projected on Pasni and Gwadar. Results show that both cities are highly vulnerable to wave heights ≥7 m and wave lengths ≥ 15 km. The 15 m scenario would be almost a complete disaster for both cities and adjoining towns. Results of simulation and comparative analysis also show that due to coastal orientation and morphology, the reflection, integration, and amplification phenomena have a devastating effect on the region, and their intensity increases with the increasing size of the approaching waveform. It variably but significantly affects the inundation extents and depths. At the end, based on the simulated results, the utility of the installed early warning system is assessed. [ABSTRACT FROM AUTHOR]

The Karakoram Highway links north Pakistan with southwest China. It passes through unique geomorphological, geological and tectonic setting. This study focused 200-km-long section of the highway starting from Besham until Chilas. Landslides are frequent and are mostly triggered by torrential rain during Monsoon and Westerlies, leading to highway blockade. Rockfall and debris flow are prime mode of slope failures. Regional to site-specific approach was implemented to assess risk associated with these two modes. Remote sensing-based techniques were used to identify potential hazardous sites, which were further investigated for risk assessment. Modified Pierson's rockfall hazard rating system (RHRS) rated potential rockfalls, whereas semi-quantitative technique was employed to assess debris flows. Normalized scores of each site shaped the final map, further classified into four zones: very high, high, intermediate and low risk. [ABSTRACT FROM AUTHOR]

The Karakoram Highway (KKH) is an important route, which connects northern Pakistan with Western China. Presence of steep slopes, active faults and seismic zones, sheared rock mass, and torrential rainfall make the study area a unique geohazards laboratory. Since its construction, landslides constitute an appreciable threat, having blocked the KKH several times. Therefore, landslide susceptibility mapping was carried out in this study to support highway authorities in maintaining smooth and hazard-free travelling. Geological and geomorphological data were collected and processed using a geographic information system (GIS) environment. Different conditioning and triggering factors for landslide occurrences were considered for preparation of the susceptibility map. These factors include lithology, seismicity, rainfall intensity, faults, elevation, slope angle, aspect, curvature, land cover and hydrology. According to spatial and statistical analyses, active faults, seismicity and slope angle mainly control the spatial distribution of landslides. Each controlling parameter was assigned a numerical weight by utilizing the analytic hierarchy process (AHP) method. Additionally, the weighted overlay method (WOL) was employed to determine landslide susceptibility indices. As a result, the landslide susceptibility map was produced. In the map, the KKH was subdivided into four different susceptibility zones. Some sections of the highway fall into high to very high susceptibility zones. According to results, active faults, slope gradient, seismicity and lithology have a strong influence on landslide events. Credibility of the map was validated by landslide density analysis (LDA) and receiver operator characteristics (ROC), yielding a predictive accuracy of 72 %, which is rated as satisfactory by previous researchers. [ABSTRACT FROM AUTHOR]

The Kalabagh Fault forms a lateral offset in the Main Frontal Thrust in the Sub-Himalayan area of Pakistan, forming a push-up block within the stepover zone of its segments. Deformed sediments along the frontal part of this push-up block have cross cutting relations with morphotectonic and paleoseismic features. These sediments are dated using luminescence dating methods. The post-infrared infrared stimulated luminescence (post-IR IRSL) of K-feldspar was used for samples representing these sedimentary units. For stratigraphically younger sediments with partially-bleached pIRIR signal, optically stimulated luminescence (OSL) of quartz was applied with the minimum age model (MAM). These ages are used to illustrate the timing of development of the push-up block, the westward diversion of the Indus River and Holocene earthquakes along the Kalabagh Fault (KBF). The deformed sediments from the mountain front at Larkakki are older than those of Khairabad and Ghundi. These age estimates are consistent with the chronological order of the tectonic deformations in the stepover zone of the Kalabagh Fault. Age estimates and correlation of the sedimentary units suggest the emergence of the push-up block in the stepover zone during the past ∼0.5 Ma. Active faulting and development of the ramp along the Kalabagh Fault has diverted the course of the Indus River towards the west at a displacement rate of 12–15 cm/a during last ∼140 ka. Luminescence data indicate Holocene timing for the earthquakes along the Kalabagh Fault, which are diachronous and suggest differential movements along the segments of the fault. The earthquake recurrence interval at Khairabad is 10 ± 2 ka on average. The younger earthquakes at the foreland in the south of the stepover indicate seismically active zone. [ABSTRACT FROM AUTHOR]

The Kalabagh Fault Zone in the western Sub-Himalayas is a dextral strike slip fault zone that exhibits a push-up block in the stepover zone of the two fault segments. The inception of the push-up block occurred along the restraining faults that form two morphotectonic bends along the mountain front at Zaluch and in the South of Thathi. The landform was further developed by en-echelon fold and thrust sequence up to Khairabad in the North and Ghundi village in the South. The aseismically moving fault zone has experienced earthquakes during late Quaternary forming surface expressions in the West of the push-up block at Khairabad, Larkakki and Ghundi. The Khairabad and Ghundi sections are the active tectonic fronts of the stepover zone. Displacements caused by these seismic activities has deformed Quaternary sediments creating stream deflections, surface ruptures, pressure ridges, uplifted sediments at the mountain front, foreland ridges and uplifted alluvial fan. Offsets in the late Quaternary sediments indicate the Kalabagh Fault is active and seismic events of M w ≥ 6 has formed these ground effects. Furthermore, stratigraphic correlations of fluvial sediments indicate the Indus River has been flowing in the NS direction along the northern segment of the Kalabagh Fault. Uplift of the push-up block in the Kalabagh Fault Zone and subsequent deposition of the alluvial fans has caused westward diversion of the Indus River. [ABSTRACT FROM AUTHOR]

Tsunamis and cyclones are sea-borne hazards capable of inundating vast coastal areas. This study aims at an extreme wave hazard assessment with a preliminary inundation analysis along the Makran Coast, Pakistan. The coastal hazard, particularly tsunamis, is evaluated by integrating five approaches: (i) probabilistic tsunami hazard assessment (PTHA); (ii) deterministic tsunami hazard assessment (DTHA); (iii) geophysical-seismic (2-D thermal modelling), (iv) sedimentary tsunami deposits (tsunamis); and (v) the historical record. The recurrence interval for a mega-tsunami event (≥12 m) is between 500 and 1000 years in the Arabian Sea. Of these mega-tsunamis, about 60% are generated by seismic sources, while the remaining 40% are attributed to secondary (co-seismic submarine landslides) and other non-seismic sources. Based on the above five approaches, the hazard analysis helped to shortlist four wave scenarios (3, 7, 10, and 15 m). Which were further used to demarcate risk areas through static inundation analysis. The results indicated that the damage potential at the coast is minor to negligible with 3 m waves and moderate with 7 m waves. Whereas the 10 m and 15 m waves will severely disrupt the study area. In addition to tsunami risk, cyclone risk is assessed by interpolating storm tracks dating back to 1842 CE. In the last 64 years, cyclone frequency has jumped from 1 cyclone per 10 years to 20 cyclones per 10 years, and the intensity has increased by two levels from Tropical Storm (TS) to Category-3. [ABSTRACT FROM AUTHOR]