We analyze strong motion records and high-rate GPS measurements of the M 7.8 Gorkha mainshock, M 7.3 Dolakha, and two moderate aftershock events recorded at four stations on the Kathmandu basin ...sediments, and one on rock-outcrop. Recordings on soil from all four events show systematic amplification relative to the rock site at multiple frequencies in the 0.1–2.5Hz frequency range, and de-amplification of higher frequencies (>2.5–10Hz). The soil-to-rock amplification ratios for the M 7.8 and M 7.3 events have lower amplitude and frequency peaks relative to the ratios of the two moderate events, effects that could be suggestive of nonlinear site response. Further, comparisons to ground motion prediction equations show that 1) both soil and rock mainshock recordings were severely depleted of high frequencies, and 2) the depletion at high frequencies is not present in the aftershocks. These observations indicate that the high frequency deamplification is additionally related to characteristics of the source that are not captured by simplified ground motion prediction equations, and allude to seismic hazard analysis models being revised – possibly by treating isolated high frequency radiation sources separately from long period components to capture large magnitude near-source events such as the 2015 Gorkha mainshock.
•2015 Gorkha sequence recorded on five strong motion and two high-rate GPS stations on soil and rock sites in Kathmandu.•Soil-rock spectral ratios reveal low frequency amplification, high frequency deamplification.•Shaking intensity controlled by 3D basin effects, anelastic site response, and source properties.
Mugling–Narayanghat road section in Nepal has suffered from a variety of slope failure including rockslides, rock topples, debris slide/flow, and some combination of these. Based on the prominent ...type of failure, the highway can be divided into three sections (a) Ch10 to Ch17 (dominated by shallow landslides and debris slides/flows), (b) Ch17 to Ch28 (dominated by large-scale, deep-seated landslides), and (c) Ch28 to Ch35 (dominated by rock topples). Rock topples are frequently observed along the highway, mainly on both the limbs of Jalbire Syncline as well as at the upstream of Maure Khola and some in Siwaliks. Slates, phyllites, quartzite, amphibolite and sandstones are affected by these topples. The Maure Khola landslide that is highly affected by rock toppling falls in Nourpoul Formation and consists of amphibolite, quartzite, and slate/phyllite. It lies at the upper reach of the Simaltal Thrust. Steep slopes characterize the upper slope, whose base is covered by thick debris forming a huge debris fan. According to the selected methodological approaches, data from detailed geological, geomorphological and geomechanical surveys, it is clear that these topples are mainly related to the geological structures of the region. Additionally, the landslide contains several sheared zones where the rocks are considerably weathered. These sheared zones act as the sliding plane. Also, the debris fan at the lower part suggests that the landslide has been reactivated several times in the past. Furthermore, it is seen that flexural toppling occurs in weak, mica-rich slate/phyllite at the upper slope, while block toppling is prominent in stronger amphibolites and quartzite lying in the central part.
•The landslides were mapped by detailed field work.•Types of landslides in each rock type and in each segment of the Highway were recorded.•One landslide that is suffered from multiple rock topple is studied in detail.•Several sheared zones are observed along the landslide where the rocks are weathered.•Block toppling is observed in massive amphibolite and quartzite.
In The Mardzong Manuscripts Agnieszka Helman-Ważny and Charles Ramble recount the discovery of a cache of Bön and Buddhist manuscripts, some over seven centuries old, in the remote Mardzong caves in ...Mustang, Nepal, and subsequent research on the collection.
The applicability of wastewater-based epidemiology (WBE) has been extensively studied throughout the world with remarkable findings. This study reports the presence and reduction of severe acute ...respiratory syndrome coronavirus 2 (SARS-CoV-2) at two wastewater treatment plants (WWTPs) of Nepal, along with river water, hospital wastewater (HWW), and wastewater from sewer lines collected between July 2020 and February 2021. SARS-CoV-2 RNA was detected in 50%, 54%, 100%, and 100% of water samples from WWTPs, river hospitals, and sewer lines, respectively, by at least one of four quantitative PCR assays tested (CDC-N1, CDC-N2, NIID_2019-nCOV_N, and N_Sarbeco). The CDC-N2 assay detected SARS-CoV-2 RNA in the highest number of raw influent samples of both WWTPs. The highest concentration was observed for an influent sample of WWTP A (5.5 ± 1.0 log10 genome copies/L) by the N_Sarbeco assay. SARS-CoV-2 was detected in 47% (16/34) of the total treated effluents of WWTPs, indicating that biological treatments installed at the tested WWTPs are not enough to eliminate SARS-CoV-2 RNA. One influent sample was positive for N501Y mutation using the mutation-specific qPCR, highlighting a need for further typing of water samples to detect Variants of Concern. Furthermore, crAssphage-normalized SARS-CoV-2 RNA concentrations in raw wastewater did not show any significant association with the number of new coronavirus disease 2019 (COVID-19) cases in the whole district where the WWTPs were located, suggesting a need for further studies focusing on suitability of viral as well as biochemical markers as a population normalizing factor. Detection of SARS-CoV-2 RNA before, after, and during the peaking in number of COVID-19 cases suggests that WBE is a useful tool for COVID-19 case estimation in developing countries.
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•First case of detection of SARS-CoV-2 RNA in wastewater and river water in Nepal•SARS-CoV-2 RNA was detected using qPCR in 60% (50/84) of water samples tested.•CDC-N2 assay showed the highest positive ratios among four qPCR assays tested.•Reduction ratios of SARS-CoV-2 RNA at WWTP were higher than those of crAssphage.•N501Y mutation was detected in an influent of WWTP collected in February 2021.
Feeling initially aimless and out of place in rural Nepal where she accompanied her anthropologist husband for a year of fieldwork, Katharine Bjork Guneratne turned to writing to make sense of her ...sojourn in the shadow of the Himalaya. The resulting book is both an acute portrait of a village and an intimate account of her struggles to adapt to a different way of life. Like the best cultural travel narratives , In the Circle of the Dance draws on the author's experiences to illuminate both exterior and interior worlds. Bjork's book is in many ways a primer on the realities of fieldwork, from setting up house to participating in the work of the village women to finding ways to communicate across cultural divides. It describes how this outsider achieved a gradual and provisional inclusion in the community, an inclusion represented by her participation in a traditional women's circle dance. The book also depicts the effects of modernization and tourism on a society that remained closed to the West well into this century, while offering comparative insights about wider South Asian cultures. The author's lyrical, frequently moving descriptions of everyday life guide her readers through the stages of her cultural apprenticeship. In the end, as Bjork joins the circle dance, she is a stranger to the community still, but a familiar and welcome one.
In the western Nepal Himalaya, a major mountain building shear zone, the Main Central thrust, is exposed in multiple locations along its southward transport direction. The hanging wall of the Main ...Central thrust was sampled in both hinterland and foreland exposures, in the upper Karnali valley and around Jumla, respectively. In situ U–Th/Pb monazite petrochronology coupled with microstructural and petrographic observations reveals distinctly different timing of deformation, despite the geographic proximity and apparent structural continuity between the two regions. The Y content, the Gd to Yb ratio and the Eu anomaly in monazite constrain the timing of metamorphic reactions. Rocks in the upper Karnali valley record deformation associated with metamorphism at 18Ma, melt crystallization starting at ca. 14Ma and lasting until at least 11–10Ma. In contrast, the Jumla region records a more protracted series of events with metamorphism initiating as early as 47Ma and lasting until 18Ma, punctuated by at least two periods of melt crystallization. In both areas, the age of melt crystallization decreases down section through the hanging wall towards the Main Central thrust. Ductile deformation in the Jumla region ceased around ca. 18Ma, while rocks at similar structural positions in the hinterland in upper Karnali valley were still being actively deformed and melting at ca. 11Ma. The southern, foreland-most, hanging-wall rocks (Jumla region) were consequently exhumed above the ductile–brittle transition while the northern hinterland-most hanging-wall rocks (upper Karnali valley) were still undergoing ductile deformation and partial melting.
•Variable timing of deformation is recorded in structurally equivalent rocks from the Greater Himalayan sequence in western Nepal.•Deformation in the foreland occurred ca. 18Ma while rocks in the hinterland were being actively deformed and melted ca. 11Ma.•Out-of-sequence deformation along the Main Central thrust shear zone occurred as recently as 8Ma in the hinterland of western Nepal.
Springs are one of the most important sources of water in Nepal as people are heavily dependent on springs for their day-to-day life. However, inventory of available springs and assessment of spring ...water quality for possible uses is lacking. In this study, analysis of the concentration of physical and chemical parameters and pathogen contamination in springs of the Raghuganga Municipality (RRM) of Gandaki Province, Nepal was conducted to assess the water quality and to understand the reasons for their spatial variation. Altogether 107 water samples from 47 springs were collected during the pre-monsoon and post-monsoon periods of the year 2021. Following chemical analysis of the samples, suitability of the springs for drinking was assessed through comparison of the water quality parameters with the WHO and NDWQS guidelines and by computation of the water quality index (WQI). Similarly, their suitability for irrigation and industrial uses was assessed using sodium absorption ratio (SAR), salinity, and Na%. Piper diagram, Gibbs plot and Mixing diagram were used, and multivariate statistical tests were employed to understand the hydro-chemical characteristics and statistical significance. The spring water chemistry was found to be governed by underlying geogenic factors dominated by carbonate rock weathering and all the spring samples were found suitable for irrigation and industrial uses based on the physical and chemical parameters. However, presence of fecal coliform in 18 pre-monsoon samples (38.3%) and one post-monsoon sample (2%) deemed the spring water unsuitable and unsafe for drinking without proper treatment.
The water resources of Tamor River Basin in the eastern Himalayas of Nepal is heavily tapped for agricultural water use and hydropower production. Several studies show that the hydrology of the ...Himalayan River Basins is vulnerable to climate change. Topographical variations, data scarcity and its complex climate have always been barriers to achieving realistic simulation of the hydrological regime in the Himalayan River Basins, and the Tamor River Basin is no different. In hydrological response unit (HRU) based models, fixing the number of HRUs and sub-basins has a tendency towards confusion. This is especially true in regions with altitudinal and climatic variations. Therefore, this study aims to evaluate the SWAT model performance uncertainty associated with the number of sub-basins, HRUs, and elevation bands and quantify the impact of climate change on streamflows in the Tamor River Basin. Future climate scenarios were developed for three different time frames, the 2030s, 2060s, and 2080s, based on an ensemble of Coupled Model Intercomparison Project Phase 5 (CMIP5) and four Regional Climate Models (RCMs) under the Representative Concentration Pathways (RCP4.5 and RCP8.5) scenarios. The linear scaling method (LSM) of bias correction was used to bias-correct the climate data and then fed into the SWAT model to simulate the future streamflows of the basin. An increase in the annual average maximum temperature (+4 °C) and minimum temperature (+5.5 °C), and a decrease in precipitation (−4.5%) is projected by the end of the twenty-first century under RCP8.5 scenarios. The study found that the future climate could decrease the streamflow by over 8.5% during the twenty-first century under RCP8.5 scenarios. The results show elevation bands (EBs) to be more significant compared to HRUs and sub-basins (SBs) in getting a robust hydrological model in the Himalayan region. The estimates prepared in this study would be beneficial for hydropower developers, planners and policymakers, and water resource managers in developing adaptation strategies to offset the negative impact of climate change in the Tamor River Basin.
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•We calibrated SWAT model under different model setup scenarios in Himalayan basin.•Elevation bands found to be significant for hydrological modelling in the Himalayan region.•The model simulated future streamflow in future climate change scenarios.•Climate change is expected to decrease streamflow of Tamor river in future.
Microplastics (MPs, plastics < 5 mm) are a growing concern in ecosystems, being found in the soil and water environment. One of the primary sources of MPs has been suspected to be road dust in urban ...areas as it can flow into waters with runoff. To understand the occurrence of MPs (100 μm–5 mm) in surface road dust of three cities (Kusatsu, Shiga, Japan; Da Nang, Vietnam; and Kathmandu, Nepal), we collected surface road dust samples. The samples were pretreated (organic matter decomposition and gravity separation), and all MP candidates were individually observed by microscope for color, shape, and size; and analyzed their polymer types using fourier transform infrared spectrometry. The abundances of MPs 100 μm to 5 mm in size were 2.0 ± 1.6 pieces/m2 (13 polymer types) in Kusatsu, 19.7 ± 13.7 pieces/m2 in Da Nang (14 types), and 12.5 ± 10.1 pieces/m2 in Kathmandu (15 types). We classified the MPs into two groups; containers/packaging-MPs and rubber-MPs. Among all MPs, the containers/packaging-MPs accounted for 55 ± 5% of the polymer types composition. In contrast, the rubber-MPs accounted for 16 ± 6% of all MPs which were higher than those previously published for environmental water and sediment samples. The containers/packaging-MPs were fragments of various colors while most of the rubber-MPs were fragments or granules in black. The number–size distributions of MPs showed that the mode of formation explains the differences between their polymer types (tearing for containers/packaging-MPs and abrasion for rubber-MPs). In Da Nang and Kathmandu, the abundance of containers/packaging-MPs and rubber-MPs were correlated so that those MPs might be micronized from the originated materials in the sources with the similar composition (e.g. dump points). It was indicated that the characteristics of MPs pollution in surface road dust might be different depending on waste management practices.
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•Microplastics in road dust were investigated in Japan, Viernam, and Nepal.•The abundance of MPs in road dust of three urban cities was 0.10–39.6 pieces/m2.•The color and shape of MPs in road dust were different between their polymer types.•The modes of MPs generation (tearing, abrasion) may depend on their components.•The MPs might be derived from the sources with similar composition (e.g. dump points).
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