Gravity anomalies and deep structure of eastern Hudson bay     

Manoj Mukhopadhyay  R.A. Gibb 《Tectonophysics》1981,72(1-2)

The Cape Smith and Belcher foldbelts of Lower Proterozoic (Aphebian) rocks form parts of the proposed Circum-Superior suture which separates the Superior and Churchill structural provinces of the Canadian Shield. Recent marine gravity surveys in eastern Hudson Bay (1976–1979) show that the distinctive linear gravity pattern of paired positive and negative anomalies along the Cape Smith foldbelt of northern Ungava extends southwards into Hudson Bay to the Belcher Islands. Interpretation of five gravity profiles across the Cape Smith and Belcher foldbelts suggests that the Churchill crust is thicker and denser than the Superior. The boundary between the two contrasting crustal blocks is interpreted as a collisional suture. The rocks of the foldbelts which are progressively more volcanic northwards are the source of a residual positive anomaly associated with the Cape Smith foldbelt and a series of discontinuous positive residual anomalies in the Bay. To the north the thicknesses of the foldbelt rocks are estimated to be between 4 and 9 km with a local maximum of 13 km in the northernmost profile. To the south in the Belcher Islands, where geological estimates of formation thickness and measured rock densities provide more constraints on the interpretation of the residual anomalies, the foldbelt rocks are generally 6–7 km thick with a local maximum thickness of about 9 km. One possible interpretation of paleomagnetic results for Belcher Islands rocks in terms of a two-plate model lends support to the collision hypothesis.  相似文献   

Multi-well and multi-tracer tests to characterize the groundwater aquifers in southern Kuwait     

K. Hadi  U. Saravana Kumar  M. Al-Senafy  A. Mukhopadhyay  A. Al-Khalid  K. Al-Fahad  H. Bhandary 《Environmental Earth Sciences》2016,75(20):1340

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Establishing a baseline to evaluate future impacts to groundwater resources in North Kuwait     

Amitabha Mukhopadhyay  Adnan Akber  Tariq Rashed  Vincent Kotwicki  Saif Uddin  Abdullah Bushehri 《Environmental Earth Sciences》2016,75(4):324

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Microphysical processes and hydrometeor distributions associated with thunderstorms over India: WRF (cloud-resolving) simulations and validations using TRMM     

Madhuparna Halder  P. Mukhopadhyay 《Natural Hazards》2016,83(2):1125-1155

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Seismicity pattern in north Sumatra-Great Nicobar region: In search of precursor for the 26 December 2004 earthquake   总被引：1，自引：0，他引：1  

Sujit Dasgupta  Basab Mukhopadhyay  Auditeya Bhattacharya 《Journal of Earth System Science》2007,116(3):215-223

We analyse the seismicity pattern including b-value in the north Sumatra-Great Nicobar region from 1976 to 2004. The analysis suggests that there were a number of significant, intermediate and short-term precursors before the magnitude 7.6 earthquake of 2 November 2002. However, they were not found to be so prominent prior to the magnitude 9.0 earthquake of 26 December 2004 though downward migration of activity and a 50-day short-term quiescence was observed before the event. The various precursors identified include post-seismic and intermediate-term quiescence of 13 and 10 years respectively, between the 1976 (magnitude 6.3) and 2002 earthquakes with two years (1990–1991) of increase in background seismicity; renewed seismicity, downward migration of seismic activity and foreshocks in 2002, just before the mainshock. Spatial variation in b-value with time indicates precursory changes in the form of high b-value zone near the epicenter preceding the mainshocks of 2004 and 2002 and temporal rise in b-value in the epicentral area before the 2002 earthquake.  相似文献   

Water Quality Monitoring of Tropical Ponds: Location and Depth Effect in Two Case Studies     

Gautam Mukhopadhyay  Debasis Mondal  Pinaki Biswas  Anjana Dewanji 《洁净——土壤、空气、水》2004,32(2):138-148

The variability in water chemistry of samples taken on a monthly basis (March 1999 to February 2000) from two shallow tropical ponds was studied. The effect of location and pond depth on water chemistry was also examined. The study demonstrated that intraannual variability in nutrient concentration is high. Thus, a high annual sampling frequency is required to provide representative annual mean water quality data. Routine monitoring during the monsoons is important for studies on dissolved oxygen and macrophyte growth. Significant differences were found between the topmost and bottommost points for samples of dissolved oxygen collected from the deepest part of both ponds. For nutrient analysis (nitrogen and phosphorus), sample from any location was found to be representative of the whole pond.  相似文献   

Clustering of Earthquake Events in the Himalaya - Its Relevance to Regional Tectonic Set-up   总被引：1，自引：0，他引：1  

Basab Mukhopadhyay  Sabyasachi Dasgupta  Sujit Dasgupta 《Gondwana Research》2004,7(4):1242-1247

The earthquake events of Himalaya of magnitude ≥5.0 from the time window 1905–2000 are statistically analysed. The inter-event time between earthquakes shows Hurst phenomena of temporal clustering which are spatially located in five distinct domains along the Himalayan fold-thrust belt. Out of these, two domains, one around Uttaranchal-Nepal border and the other around Nepal-Sikkim border reveal maximum number of temporal clusters and thus considered as seismically most potential zones of the Himalaya. Both these zones are located at the interface of the orthogonally disposed major tectonic discontinuities of the Peninsular Shield and Himalayan fold-thrust belt. Such zones are geologically most favourable locales for strain accumulation during later-tectonic movement. Statistical analysis points towards a probability of recurrence of seismic events in near future in these two zones. However, validity of such statistical results can be ascertained by detailed geological and geophysical modelling of the terrain.  相似文献   

Slum dweller's daily movement pattern in a Calcutta slum     

Anupa Mukhopadhyay  Ashok K. Dutt 《GeoJournal》1993,29(2):181-186

This study identifies the daily activity pattern of a city slum in Calcutta and analyzes the socio-economic correlates and proposes activity pattern models. The study area, Tangra slum is located in a low-lying poorly drained area where cheap land has led to the development of a large number of factories, and a cattle slaughter house; places of employment for unskilled labor. The ideal location of the slum in relation to entertainment, medical clinics, transportation nodes, shopping facilities has generated a diverse activity pattern. Activities were observed to be of two natures, essential and non-essential. The two types of activities differed in their frequency with the essential activities having high frequency and the non-essential having low frequencies. Typically it was also observed that high frequency activities were limited to a radii of 5 km (3 miles) from the slum whereas, the low frequency activities radiated for 100–160 km (60 to 100 miles) from the slum.  相似文献   

Tannery Effluent Treatment by Microfiltration through Ceramic Membrane for Water Reuse: Assessment of Environmental Impacts          下载免费PDF全文

Priyankari Bhattacharya  Sourja Ghosh  Snehashikta Swarnakar  Aniruddha Mukhopadhyay 《洁净——土壤、空气、水》2015,43(5):633-644

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Structural identification with incomplete output‐only data and independence of measured information for shear‐type systems          下载免费PDF全文

Suparno Mukhopadhyay  Hilmi Luş  Raimondo Betti 《地震工程与结构动力学》2016,45(2):273-296

Structural identification is the inverse problem of estimating physical parameters of a structural system from its vibration response measurements. Incomplete instrumentation and ambient vibration testing generally result in incomplete and arbitrarily normalized measured modal information, often leading to an ill‐conditioned inverse problem and non‐unique identification results. The identifiability of any parameter set of interest depends on the amount of independent available information. In this paper, we consider the identifiability of the mass and stiffness parameters of shear‐type systems in output‐only situations with incomplete instrumentation. A mode shape expansion‐cum‐mass normalization approach is presented to obtain the complete mass normalized mode shape matrix, starting from the incomplete non‐normalized modes identified using any operational modal analysis technique. An analysis is presented to determine the minimum independent information carried by any given sensor set‐up. This is used to determine the minimum necessary number and location of sensors from the point of view of minimum necessary information for identification. The different theoretical discussions are illustrated using numerical simulations and shake table experiments. It is shown that the proposed identification algorithm is able to obtain reliably accurate physical parameter estimates under the constraints of minimal instrumentation, minimal a priori information, and unmeasured input. The sensor placement rules can be used in experiment design to determine the necessary number and location of sensors on the monitored system. John Wiley & Sons, Ltd.  相似文献