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Roy, A.
- Jabalpur Earthquake of May 22, 1997: Constraint from Aftershock Study
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Authors
Affiliations
1 Geological Survey of India, 27, J. L. Nehru Road, Calcutta - 700 016, IN
1 Geological Survey of India, 27, J. L. Nehru Road, Calcutta - 700 016, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 51, No 3 (1998), Pagination: 295-304Abstract
Macroseismic and microseismic (aftershock) investigations were carried out by the Geological Survey of India immediately after the Jabal pur earthquake (M 6.0) of May 22, 1997. The meizoseismal area of an intensity VIII (MSK) is 35 km long and 15 km wide, trending ENE-WSW. The aftershock investigation was earned out by a five-station temporary microearthquake (MEQ) network. Five felt aftershocks (M≥3.0) and 23 aftershocks in the magnitude range 1.5 to < 3.0 were recorded by the network. These are mostly clustered in an elongated area, 15 ×10 krn, near the main shock epicentre. and occurred at a depth range 35-40 k.m which is compatible with that of the main shock. The fault-plane solution of the main shock and the aftershocks revealed reverse faulting with left-lateral strike-slip component The hypocentral section and the fault-plane solutions indicate that the pre-existing ENE-WSW trending Nannada South Fault is deep-ischolar_mained to mantIe depth, and has been activated at the crust-mantle boundary to produce the main shock and the aftershocks. The failure appears to be caused in response to the northward post collisional movement of the Indian plate.Keywords
Earthquake, Aftershocks. Microseismicity, Fault-Plane Solution, Jabajpur, Madhya Pradesh.- Evidences of Multiple Deformations Near Amaidegri in the Western Part of the Gangpur Group
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Authors
Affiliations
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur-721302, IN
1 Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur-721302, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 21, No 12 (1980), Pagination: 617-622Abstract
Three phases of folding have been detected in a large exposure along the Sapai lladi near Amaidegri (22°01': 84°08') in the Ghoriajhor manganese belt in the western part of the Gangpur Group. Reclined to inclined folds (F1) plunging SSE have been coaxially refolded by open upright F2 folds, and finally, upright folds with ENE-trending axial planes (F3) cause culmination and depression of axes of open-folded reclined folds. The multiple deformations cause characteristic outcrop patterns and they are reflected in two distinct S-pole girdles around a plane of symmetry which is the axial trend of F3 folds.- Computer-Assisted Trend Surface Mapping-An Aid to Geochemical Exploration in the Sargipalli Lead-Zinc Mine Area, Sundergarh District, Orissa (India)
Abstract Views :164 |
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Authors
A. Roy
1
Affiliations
1 Geological Survey of India, 28 B, Theatre Road, Calcutta 700017, IN
1 Geological Survey of India, 28 B, Theatre Road, Calcutta 700017, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 24, No 8 (1983), Pagination: 421-425Abstract
Computer-aided trend surface mapping of the Pb values from the Sargipalli Pb-Zn mineralized belt (Orissa) revealed that the fourth-degree surface (trends and residuals) is of utmost significance for prediction of further promising pay zones of the unexplored extension areas.- A Computer Based Factor Model to Elucidate Secondary Trace-Element Distribution Patterns around the Sargipalli Lead-Zinc Sulphide Deposit, Sundergarh District, Orissa (India)
Abstract Views :235 |
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Authors
A. Roy
1
Affiliations
1 Geological Survey of India, 28 B, Theatre Road, Calcutta 700 017, IN
1 Geological Survey of India, 28 B, Theatre Road, Calcutta 700 017, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 25, No 6 (1984), Pagination: 338-348Abstract
The paper examines the results of computer based factor analysis performed on multi-element data from detailed soil geochemical survey over the lead-zinc mine at Sargipalli. Eleven elements (Pb. Cu, Zn, Ni, Co, So, Zr, Ag, Sr, Bi and Ga), measured on each of 216 soil samples by spectrographic and atomic absorption spectrophotometric methods were considered. The results from the factor analysis (R-mode) indicated that the multi-element soil geochemical distribution patterns around the Sargipalli deposit could be explained by a six-factor model. The proper evaluation of this model in relation to sound geological/geomorphological facts known from the area of study, would provide a significant insight into the probable nature of dominant underlying factors influencing the areal distribution of trace elements in soils around the ore body, and hence may serve as an indirect aid in locating further potential prospecting targets in the area.- On the Formation of K-Feldspar Augens - An Example from the Central Crystallines of the Bhutan Himalaya
Abstract Views :173 |
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Authors
A. Roy
1
Affiliations
1 Geological Survey of India, Nagpur 440022, IN
1 Geological Survey of India, Nagpur 440022, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 26, No 9 (1985), Pagination: 652-658Abstract
Mesoscopic and microscopic studies on the K-feldspar augens of Thimphu augengneiss of Bhutan suggests microshearing followed by a rotational mechanism. Megacrysts of K-feldspar are often broken into smaller segments by ductile shear faulting, followed by a combination of simple shear and flattening deformation giving rise to the augens.- Factorial Correspondence Analysis of Spatially Related Multi-Metallic Data along Gangpur-Singhbhum Metallo-Tectonic Belt
Abstract Views :167 |
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Authors
Affiliations
1 Geological Survey of India, ER, 12 Russel St., Calcutta-700071, IN
2 Department of Geology, Presidency College, Calcutta-700073, IN
3 95A, Ballygunge Gardens, Calcutta-700019, IN
1 Geological Survey of India, ER, 12 Russel St., Calcutta-700071, IN
2 Department of Geology, Presidency College, Calcutta-700073, IN
3 95A, Ballygunge Gardens, Calcutta-700019, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 43, No 4 (1994), Pagination: 395-406Abstract
Correspondence analysis, using the concept of joint probability distribution of two random variables, individual samples and chemical variables, was applied to two sets of multi-metallic data from Mosaboni copper mines (18th, 21st & 25th revels) and Sargipalli lead-zinc mine falling within the Gangpur-Singhbhum metallo-tectonic belt. The analysis results factor loadings for individual samples and variables, which when plotted as points on two-dimensional coordinate (factorial) axes with the same origin recognize distinct geochemical domains characterised by natural groupings or clusters of samples and variables. The simultaneous variation of trace elements in these two data sets with sample locations (background/anomalous) seems to reflect overall trends of geochemical evolution of base metal mineralisation in the region.Keywords
Statistical Studies, Economic Geology, Copper, Lead-Zinc, Sargipalli, Mosaboni, Bihar, Orissa.- A Note on the Genesis of Augen-Gneiss Around Kurumda in the Mayurbhanj District, Orissa
Abstract Views :199 |
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Authors
A. Roy
1
Affiliations
1 Department of Geology, Presidency College, Calcutta, IN
1 Department of Geology, Presidency College, Calcutta, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 14, No 1 (1973), Pagination: 96-101Abstract
No Abstract.- Rare Earth Element Geochemistry of Selected Mafic-Ultramafic Units from Singhbhum Craton: Implications to Source Heterogeneity
Abstract Views :167 |
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Authors
Affiliations
1 Department of Applied Geology, Indian School of Mines, Dhanbad, IN
2 Physical Research Laboratory, Ahmedabad, IN
3 Tokyo Metropolitan University, JP
4 Tokyo Metropolitan University, IN
1 Department of Applied Geology, Indian School of Mines, Dhanbad, IN
2 Physical Research Laboratory, Ahmedabad, IN
3 Tokyo Metropolitan University, JP
4 Tokyo Metropolitan University, IN