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  • 1.
    Kumar, Rajesh
    et al.
    Department of Environmental Science, Sharda University, Greater Noida.
    Kumar, Ramesh
    Department of Environmental Science, Sharda University, Greater Noida.
    Singh, Shaktiman
    Department of Environmental Science, Sharda University, Greater Noida.
    Singh, Atar
    Department of Environmental Science, Sharda University, Greater Noida.
    Bhardwaj, Anshuman
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Kumari, Anupma
    Environmental Biology Laboratory, Department of Zoology, Patna University.
    Randhawa, S.S.
    State Council for Science, Technology and Environment, Shimla.
    Saha, Ashok
    Ministry of Earth Science, New Delhi.
    Dynamics of suspended sediment load with respect to summer discharge and temperatures in Shaune Garang glacierized catchment, Western Himalaya2018In: Acta Geophysica, ISSN 1895-6572, E-ISSN 1895-7455, Vol. 66, no 5, p. 1109-1120Article in journal (Refereed)
    Abstract [en]

    The observed and predicted rise in temperature will have deleterious impact on melting of snow and ice and form of precipitation which is already evident in Indian Himalayan Region. The temperature-dependent entities like discharge and sediment load will also vary with the observed and predicted rise posing environmental, social and economic threat in the region. There is little known about sediment load transport in relation to temperature and discharge in glacierized catchments in Himalaya mainly due to the scarcity of ground-based observation. The present study is an attempt to understand the suspended sediment load and transportation in relation to variation in discharge and temperature in the Shaune Garang catchment. The result shows strong dependence of sediment concentration primarily on discharge (R2 = 0.84) and then on temperature (R2 = 0.79). The catchments with similar geological and climate setting were observed to have comparatively close weathering rate. The sediment load was found to be higher in the catchments in eastern and central part of Indian Himalayan Region in comparison with western part due to dominance of Indian Summer Monsoon leading to high discharge. The annual physical weathering rate in Shaune Garang catchment was found to be 411 t km−2 year−1 which has increased from 327 t km−2 year−1 in around three decades due to rise in temperature causing increase in discharge and proportion of debris-covered glacierized area.

  • 2.
    Kumar, Ramesh
    et al.
    Department of Environmental Science, SBSR, Sharda University, Greater Noida, India.
    Kumar, Rajesh
    Department of Environmental Science, SBSR, Sharda University, Greater Noida, India.
    Singh, Atar
    Department of Environmental Science, SBSR, Sharda University, Greater Noida, India.
    Singh, Shaktiman
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology. Sharda University, Greater Noida, India.
    Bhardwaj, Anshuman
    Luleå University of Technology, Department of Computer Science, Electrical and Space Engineering, Space Technology.
    Kumari, Anupma
    Department of Zoology, Patna University, Patna, India.
    Sinha, Ravindra Kumar
    Department of Zoology, Patna University, Patna, India, Nalanda Open University, Biscoman Bhawan, Gandhi Maidan, Patna, India.
    Gupta, Akhilesh
    DST, Technology Bhavan, New Mehrauli Road, New Delhi, India.
    Hydro-geochemical analysis of meltwater draining from Bilare Banga glacier, Western Himalaya2019In: Acta Geophysica, ISSN 1895-6572, E-ISSN 1895-7455, Vol. 67, no 2, p. 651-660Article in journal (Refereed)
    Abstract [en]

    The changing climate is affecting the melting process of glacier ice and snow in Himalaya and may influence the hydro-geochemistry of the glacial meltwater. This paper represents the ionic composition of discharge from Bilare Banga glacier by carrying out hydro-geochemical analysis of water samples of melting season of 2017. The pH and EC were measured on-site in field, and others parameters were examined in the laboratory. The abundance of the ions observed in meltwater has been arranged in decreasing order for cations as Ca2+ > Mg2+ > Na+ > K+ and for anions as HCO3 > SO42− > Cl > NO3, respectively. Analysis suggests that the meltwater is mostly dominated by Ca2+ and HCO3. It has been observed that the ionic concentration HCO3 is dominant and Cl is the least in the catchment. Piper plot analysis suggests that the chemical composition of the glacier discharge not only has natural origin but also has some anthropogenic input. Hydro-geochemical heterogeneity reflected the carbonate-dominated features (Ca2+–HCO3) in the catchment. The carbonate weathering was found as the regulatory factor to control the chemistry of the glacial meltwater due to the high enrichment ratio of (Ca2+ + Mg2+) against TZ+ and (Na+ + K+). In statistical approach, PCA analysis suggests that geogenic weathering dynamics in the catchment is associated with carbonate-dominant lithology.

  • 3.
    Nordström, Emilia
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Dineva, Savka
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Nordlund, Erling
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Source parameters of seismic events potentially associated with damage in block 33/34 of the Kiirunavaara mine (Sweden)2017In: Acta Geophysica, ISSN 1895-6572, E-ISSN 1895-7455, Vol. 65, no 6, p. 1229-1242Article in journal (Refereed)
    Abstract [en]

    Forty-six mining-induced seismic events with moment magnitude between −1.2 and 2.1 that possibly caused damage were studied. The events occurred between 2008 and 2013 at mining level 850–1350 m in the Kiirunavaara Mine (Sweden). Hypocenter locations were refined using from 6 to 130 sensors at distances of up to 1400 m. The source parameters of the events were re-estimated using spectral analysis with a standard Brune model (slope −2). The radiated energy for the studied events varied from 4.7 × 10−1 to 3.8 × 107 J, the source radii from 4 to 110 m, the apparent stress from 6.2 × 102 to 1.1 × 106 Pa, energy ratio (Es/Ep) from 1.2 to 126, and apparent volume from 1.8 × 103 to 1.1 × 107 m3. 90% of the events were located in the footwall, close to the ore contact. The events were classified as shear/fault slip (FS) or non-shear (NS) based on the Es/Ep ratio (>10 or <10). Out of 46 events 15 events were classified as NS located almost in the whole range between 840 and 1360 m, including many events below the production. The rest 31 FS events were concentrated mostly around the production levels and slightly below them. The relationships between some source parameters and seismic moment/moment magnitude showed dependence on the type of the source mechanism. The energy and the apparent stress were found to be three times larger for FS events than for NS events.

  • 4.
    Oskooi, B.
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. Institute of Geophysics, University of Tehran, Tehran, Iran.
    Moradi, M.
    Institute of Geophysics, University of Tehran, Tehran, Iran.
    Smirnov, Maxim
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Integrated interpretation of seismic and magnetotelluric data on Shurab diapirs in Qom basin, Central Iran2019In: Acta Geophysica, ISSN 1895-6572, E-ISSN 1895-7455, Vol. 67, no 4, p. 1071-1090Article in journal (Refereed)
    Abstract [en]

    In recent decades, diapirs are frequently used for CO2 and natural gas storage due to their extremely impermeable and non-reactive characteristics. Among various approaches, we use an integrated interpretation approach to resolve the diapir no. 4 belonging to the Shurab diapirs (SD). The SD is a group of diapirs that have pierced to the surface of the Qom basin of Central Iran, which is a candidate for natural gas storages. The complex geology of the SD is the main cause that previous 2D seismic surveys across the diapir could not provide required information to propose any location for any exploration borehole. Consequentially, 28 magnetotelluric (MT) and 1 audio-magnetotelluric station were measured along a SW-NE profile. Dimensionality and strike analysis for all stations is done by the use of phase tensor analysis. We used the nonlinear conjugate gradient algorithm to invert the TE- and TM-modes data simultaneously in 2D. The resistivity model was compared with the interpreted results of the post-stack depth migration model using seismic attributes. In order to extract the determinative geological information from the low-quality seismic section, envelope, variance, sweetness and instantaneous frequencies attributes were used. The integrated interpretation of the seismic and MT data resolves a precise geometry of the salt body, location of the dense part of the diapir as well as the tectonics around the diapir. The integrated interpretation of seismic and MT data of diapir no. 4 resulted in an exploration drilling program.

  • 5.
    Tavakoli, Saman
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Dehghannejad, Mahdieh
    Department of Earth Sciences, Division of Geophysics, Uppsala University .
    de los Ángeles García Juanatey, María
    Department of Earth Sciences, Division of Geophysics, Uppsala University .
    Bauer, Tobias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Weihed, Pär
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Elming, Sten-Åke
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Potential Field, Geoelectrical and Reflection Seismic Investigations for Massive Sulphide Exploration in the Skellefte Mining District, Northern Sweden2016In: Acta Geophysica, ISSN 1895-6572, E-ISSN 1895-7455, Vol. 64, no 6, p. 2171-2199Article in journal (Refereed)
    Abstract [en]

    Multi-scale geophysical studies were conducted in the central Skellefte district (CSD) in order to delineate the geometry of the upper crust (down to maximum ∼ 4.5 km depth) for prospecting volcanic massive sulphide (VMS) mineralization. These geophysical investigations include potential field, resistivity/induced polarization (IP), reflection seismic and magnetotelluric (MT) data which were collected between 2009 and 2010. The interpretations were divided in two scales: (i) shallow (∼ 1.5 km) and (ii) deep (∼4.5 km). Physical properties of the rocks, including density, magnetic susceptibility, resistivity and chargeability, were also used to improve interpretations. The study result delineates the geometry of the upper crust in the CSD and new models were suggested based on new and joint geophysical interpretation which can benefit VMS prospecting in the area. The result also indicates that a strongly conductive zone detected by resistivity/IP data may have been missed using other geophysical data.

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