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The work presented in paper is focussed on the development of an accurate time-frequency representation of accelerograms, representing the seismic activity of the Himalayalan regions. The Himalayas have a long history of high levels of seismicity due to the movement of tectonic plates in the region. The effectiveness of the advanced time-frequency analysis (TFA) method known as Wavelet Synchro-Squeezed Transforms (WSST) has been exploited for processing accelerograms of the regions. Obtaining simultaneous time and frequency localizations with high levels of resolution is always challenging for non-stationary signals such as accelerograms. To have better time and frequency localization, the first part of the paper proposes an advanced TFA technique using WSST. The second part of work is then focused on devising a technique for accurate synthesis of the accelerograms to represent the actual and limited seismic records. A WSST based denoising is further proposed to remove the unwanted noise from the signals. Using the available actual recorded data from the region, respective synthetic accelerograms and response spectra have been developed for different magnitude and distance ranges using the WSST technique. The synthetic signals are then authenticated with the actual signal data using different Joint-TFA (JTFA) approaches. The effectiveness of the proposed WSST based synthesis method is further confirmed by higher structural similarity metric (SSIM) scores when compared with the time-frequency representations of the reference ground truth accelerograms. [ABSTRACT FROM AUTHOR]

In this paper, we analyzed two decadal long term (2003–2022) data of AOD and cloud parameters to understand the spatial and temporal variations in aerosol radiative characteristics over a highly polluted urbanized region of Northern India. The aerosol and cloud data were derived at spectral wavelength of 550 nm from the MODIS based Terra/Aqua satellites. Detailed AOD quantitative analysis considering monthly, seasonal and interannual changes was investigated in relation to cloud characteristics and zonal synoptic climatic disturbances. HYSPLIT back trajectory 5-day analysis was made to know the pathways of air masses ending at Delhi region of India. Moreover, we applied Student's t-test to mean Terra AOD and cloud properties to examine and further validate the relationship of aerosol-cloud interaction over the urban tropical Delhi zone close to Himalaya range of Northern India. Results indicated that AODs were found to be increased significantly (> 68%) during the 20 years period of 2003–2022, which might be accounted to continuously increased aerosol pollution in atmosphere. On an annual basis, mean Terra AOD exhibited an increasing trend of ~ 0.0009 per year, whereas seasonal mean AOD was observed to be maximum for winter (~ 0.96) and minimum for summer (~ 0.55), respectively. The correlation coefficient was highest (+ 0.73) between AOD and precipitable water vapor, whereas lowest (− 0.46) between AOD and cloud top pressure (CTP). The findings of AOD and cloud parameters have been compared with the earlier findings made on different Indian cities. [ABSTRACT FROM AUTHOR]

The majority of the world's snow-covered mountain regions are at significant natural risk from snow avalanches. The current research attempts to prepare a Snow Avalanche Susceptibility Zonation (SASZ) map of Mughal Road, North-western Himalaya, India using an amalgam of causative factors like Slope angle, Curvature, Slope aspect, Elevation, Topographic Roughness Index (TRI), Distance to Drainage (DTD), Distance to Road (DTR), Topographic Wetness Index (TWI), Earthquake, Topographic Position Index (TPI), Wind Speed, Temperature, Solar Radiation and Ground cover. The conditioning factors were integrated within the GIS environment to delineate Snow Avalanche Susceptibility zones by employing the Weighted Overlay Model (WOM). These factors were weighted based on their relative importance to the occurrence of Snow Avalanches. Moreover, the weights have been adjusted to remove the scale biases. The final Snow Avalanche Susceptibility zonation map identified three zones, viz. high susceptibility zone (23.5%), medium susceptibility zone (31.8%) and low susceptibility zone (44.7%). The model validation was done by relating the Snow Avalanche occurrences in these classes using the ROC-AUC method. The deliverables of the study can be pivotal in managing the Snow avalanche hazard in the region and in minimizing the bio-physical losses emanating thereof. [ABSTRACT FROM AUTHOR]

This study has documented the structural and stratigraphic investigations of the Darwaza, Tajwal, Masot, Bhurban, Dewal, and Malkot areas of Murree and KPK, Pakistan. The proposed territory is positioned along the western limb of the Hazara Kashmir syntaxis (HKS). The HKS is an anti-formal hairpin-like architecture, which is seismically an active folded-and-thrust belt in the sub-Himalayas of Pakistan. It was studied using the Kink method (stratigraphic and structural analysis) combined with detailed field observations. The results reveal that the sedimentary rock sequence is fully exposed to the area from the Middle Jurassic (Samana Suk Formation) to date (Quaternary alluvium). Structurally, the study area is highly deformed. Two main deformational episodes (D1 and D2) were recognized. D1 deformation is characterized by tight to isoclinal folds with penetrative axial plane cleavage, axes plunging N43°E/80°NW, and interlimb angle 03–05°, whereas D2 deformation is categorized by open to gentle-style folds with an axial plane ranging from N28°E/68° SE to N50°E/86°NW and an interlimb angle of 95–122°. Moreover, faults and folds are present in the area. Sandh overturned syncline, Sandh anticline, Sandh syncline, Daryagali anticline, Tandoi syncline, Bhurban anticline, and Potha syncline are the major folds. These folds are northwest verging and southeast or southwest plunging. These are isoclinal to gentle folds. The Darwaza fault, Masot fault, and Main Boundary Thrust (MBT) are the major faults in the study area. These faults are northeast–southwest trending and dip to the northwest, thus forming thrust-fault–related folds. [ABSTRACT FROM AUTHOR]

The Himalayas are one of the most disaster-prone regions in the world and have experienced an increasing number of disasters, particularly floods in recent years that have hampered the socio-economic development in the region. Flood management policies are key in mitigating and managing disasters and are an important part of disaster risk reduction. In the present study, we discuss the disaster vulnerability and policy framework in the North-Western Himalayas, with a focus on the flooding in the Kashmir Valley, which is one of the most vulnerable regions in the Himalayas. Kashmir has a long history of flooding that has affected society and the environment on a wide scale. However, flood management began at the beginning of the nineteenth century. The present work explores the primary sources to make a historical analysis of flood management in Kashmir. The study provides an in-depth analysis of the important policies and proposals for flood management in the region. It discusses the top priorities established by various flood management suggestions and examines how the focus was given to Srinagar city and the reclamation of agricultural land while neglecting other areas. The study highlights the failure of the flood management plans and why the problem of flood management persists in the Kashmir Valley. The study also discusses the vulnerability of the Kashmir Valley to floods and the resultant causes. [ABSTRACT FROM AUTHOR]

The objective of the work is to understand the provenance and tectonic setting of the Karewa deposits of South Kashmir, NW Himalayas using major, trace and rare earth elements. Major elemental analysis shows that sediments are rich in SiO2 followed by Al2O3, Fe2O3, CaO, MgO, K2O, Na2O, P2O5, TiO2 and MnO. The geochemical classification diagram of Heron and Pettijohn suggested that the sediments were classified as lith-arenites, trending toward wackes, which suggested the immaturity of the sediments. The SiO2/Al2O3 ratio of 3.99 to 4.9 and Al2O3/TiO2 ratio of 12.2 to 18.7 reflected that the Karewa sediments were derived largely from intermediate and felsic sources. On V-Ni-(Th*10) ternary plot, the samples fall near the felsic source with an extension towards the mafic source rock field. Moreover, the fractionated chondrite normalized rare earth element patterns with enriched light rare earth elements (LREE) and nearly flat heavy rare earth elements (HREE) and negative europium anomalies (0.59 to 0.74) suggested that these rocks were derived from felsic to intermediate rocks of the upper continental crust with some contamination by a mafic component. The Th/Sc and Zr/Sc plot of the sediments suggest both compositional variation and new addition of Zr in the sedimentary system. Using high and low silica multidimensional discrimination diagrams and single axis discrimination plot, the source rocks of Karewa deposits show affinity towards passive margin and collision—arc tectonic settings. The ratios of Cu/Zn, U/Th and Ni/Co indicate that the Karewa sediments were deposited in oxidizing environmental conditions. [ABSTRACT FROM AUTHOR]

We use machine learning to identify spatial clusters of earthquakes, besides using multi-criteria decision-making models (MCDM) to estimate earthquake vulnerability in the Himalayan seismo-tectonic zone. Seismicity data from the USGS catalogue having 7687 earthquakes indicate eight active source zones or clusters of earthquakes. The earthquake clusters located in the eastern Himalayas are relatively larger in areal extent than those in the western Himalayas. The vulnerability was assessed using two MCDM models, i.e. fuzzy analytical hierarchy process (AHP) and fuzzy technique for order preference by similarity to ideal solution (TOPSIS). Twenty-six parameters were utilised to estimate physical, societal, geotechnical and structural vulnerabilities and integrated earthquake vulnerability map. The results show that more than 50% of the population residing in the region are relatively highly vulnerable due to earthquakes, ~ 25.81% are moderately vulnerable, and ~ 23.44% have low to very low vulnerability. Identifying the most active source zones and estimating vulnerability could be extremely useful for hazard mitigation in the Himalayan region. [ABSTRACT FROM AUTHOR]