Contents of April-July 2004 - Vol. XXV No.2 & 3

PRESIDENTIAL ADDRESS "EMERGING TREND IN OIL AND GAS EXPLORATION IN INDIA- A BRIGHT FUTURE AHEAD"
Avinash Chandra

RECENT SEISMO TECTONIC ACTIVITY ALONG THE INDO-BURMAN RANGE
B.N. Bharali

ESTIMATION OF BASEMENT DEPTH BENEATH THE KOTON-KARIFI AREA OF BIDA BASIN (NIGERIA) FROM AEROMAGNETIC DATA
Lukman A. Sunmonu, M.A.Adabanija, D. Pramod Kumar and J.A.Olawofela

ON THE RESULTS OF VLS-EM SURVEYS FOR URANIUM EXPLORATION IN DULAPALI AREA, RAIGARH DISTRICT, MP, INDIA
V.Ramesh Babu, Subash Ram, R. Srinivas, Shankar Mishra, S.C.Verma and K.K.Tiku

ASPERITY MODEL FOR SEISMICITY IN CUDDAPAH BASIN AND ADJOINING AREAS: GRAVITY EVIDENCE
M. Kesavamani, C.Ramachandran, R.M.C.Prasad,NBK Rao and J.V.Rama Rao

THE GENERALISED POLYNOMIAL TRANSFORM (GPT)
Pinneng Yu and Lynyun Lu

GEOMORPHOMETRIC CHARACTERISTICS OF 30TH SEPTEMBER, 1993 KILLARI EARTHQUAKE AREA, MAHARASHTRA
R.D. Kaplay, Md. Babar, D.B.Panaskar and A.M.Rakhe


PRESIDENTIAL ADDRESS "EMERGING TREND IN OIL AND GAS EXPLORATION IN INDIA- A BRIGHT FUTURE AHEAD"

Avinash Chandra

Past President, Association of Exploration Geoscientists, Hyderabad
Director General(Retd.), Directorate General of Hydrocarbons, New Delhi
Chief Consultant,Oil Industry Development Board, New Delhi

Abstract

India has a long history of petroleum exploration & production going back to 1889 with the discovery of the Digboi field in Assam. Since then, great strides have been made in oil and gas exploration and production activities and over 310 oil and gas fields have been discovered including seven ‘giant fields’ namely, Mumbai High, Vasai, Ankleshwar, Gandhar, Lakwa-Lakhmani, South & Mid Tapti and Nahorkatiya. The country is endowed with 26 sedimentary basins besides deep-water sedimentary areas. The total sedimentary area is of the order of 3.14 million sq.km. up to Exclusive Economic Zone (i.e. up to 200 nautical miles from the coast). Based on intensity of exploration and prospectivity as currently known, these basins have been categoried into 4 categories. There are seven category-I basins with established commercial production namely, Cambay, Assam Shelf, Assam Arakan Fold Belt (AAFB), Mumbai Offshore, Krishna-Godavari, Cauvery, and Rajasthan. Two basins namely, Kutch and Andaman-Nicobar with known accumulation of hydrocarbons but without commercial production are grouped under category-II. Seven Category-III basins namely, Himalayan Foreland, Ganga, Vindhyan, Saurashtra, Kerala-Konkan-Lakshadweep, Mahanadi and Bengal are considered geologically prospective by virtue of hydrocarbon shows. The category-IV basins include the remaining 10 basins namely, Karewa, Spiti-Zanskar, Satpura-South Rewa-Damodar, Narmada, Deccan Syneclise, Bhima-Kaladgi, Cuddapah, Pranhita-Godavari, Bastar and Chhattisgarh having uncertain potential and may be prospective by analogy with similar basins in the world.

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RECENT SEISMO TECTONIC ACTIVITY ALONG THE INDO-BURMAN RANGE

B.N. Bharali
Oil India Limited, Duliajan, Assam

Abstract

The Indo-Burman Range, characterized by shallow and intermediate depth earthquakes, ophiolitic rock and pelagic sediments is an important geotectonic feature, marking eastward subduction of the Indian plate beneath the Burman plate. The subduction is well indicated by the distribution of earthquake foci. This paper presents focal mechanism solutions, obtained for ten recent earthquakes occuring in the region of Indo-Burman range. The stress pattern obtained from the solutions, when examined in the context of some major tectonic features of the region, helps to infer the recent tectonic activity which occurred along the Indo-Burman range. 

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ESTIMATION OF BASEMENT DEPTHS BENEATH THE KOTON-KARIFI AREA OF BIDA BASIN (NIGERIA) FROM AEROMAGNETIC DATA

Lukman A. Sunmonu, M.A. Adabanija, D. Pramod Kumar and J.A.Olowofela
* Department of Pure and Applied Physics, Ladoke Akintola University of Technology, Ogbomoso Oyo state, Nigeria
** National Geophysical Research Institute, Hyderabad
*** Department of Physics, University of Ibadan, Nigeria

Abstract

An estimate of the depth to the basement of the Koton-Karifi area of Bida basin (Nigeria) has been made by two-dimensional spectral analysis of the aeromagnetic anomalies. The results show that the magnetic sources are mainly distributed at two levels. The shallow sources ranging in depth from 70 m to less than 800 m below ground level are inferred to be due to intrusives within the sediments. The deeper sources ranging in depth from 1400 m to 3500 m below ground are attributed to the underlying basement. Using the newly developed Auto Trace and Digitizing Methodology (ATD) the shaded relief image of the aeromagnatic data is generated and presented.

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VLF-EM SURVEYS FOR URANIUM EXPLORATION IN DULAPALI AREA, RAIGARH DISTRICT, MADHYA PRADESH, INDIA

V.Ramesh Babu, Subash Ram*, R.Srinivas, P.Veera Bhaskar, A.K.Bhattacharya

Atomic Minerals Directorate for Exploration & Research Department of Atomic Energy Hyderabad , Nagpur*

Abstract

Uranium mineralisation is reported in the basement fracture of Sambalpur granitoids in Dulapali area (lat.21o 25’ 45” N, long.83o 20’ 42” E) of Raigarh district, M.P. VLF-EM surveys are conducted using Scintrex IGS-2/VLF-4 equipment to demarcate the spatial locations of these fractures filled with ferruginous breccia of magnetite, hematite, ilmenite, pyrite and chalcopyrite vis--vis, the EM conductors. Three parameters – vertical in-phase (DZR) vertical out-of-phase (DZI) normalised by horizontal magnetic field (Hy) and VLF-EM resistivity (r a) are recorded and analysed. Application of Fraser filter for the in-phase component has aided in refining the location of conductor axes. Fraser filtered pseudo-sections reveal the nature of conductivity, dip and the depth of these conductors.

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ASPERITY MODEL FOR SEISMICITY IN CUDDAPAH BASIN AND ADJOINING AREAS: GRAVITY EVIDENCE

M.Kesavamani, C.Ramachandran**, R.M.C.Prasad**, N.B.K.Rao** and J.V.Rama Rao***

Training Institute, Geological Survey of India, Hyderabad
** Geophysics Division,Geological Survey of India, Hyderabad
*** Geophysics Division, Geological Survey of India, Shillong


Abstract

The modern concepts of fault segmentation and asperites/barriers are integrated with gravity interpretation to explain the seismicity in Cuddapah basin. The concentration of seismicity in Ongole region is attributed to the presence of the “Ongole asperity” adjoining a major geometrical bend against which the E-W trending Kalva-Ongole fault system is segmented or terminated. Most epicentres, in the other parts of Cuddapah Basin, are correlatable to E-W faults and are typically located at the intersection of N-S to NE-SW trending faults which might have acted as barriers. Reactivation of E-W trending faults appear to be the main source for seismicity in Cuddapah Basin, because of their favourable orientation to the present stress field. The studies show the utility of gravity maps in identifying important geological features generally associated with earthquakes.

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THE GENERALISED POLYNOMIAL TRANSFORM (GPT)

Pinneng Yu*and Lynyun Lu**

* Nanjing Engineering Institute, Nanging, P.R. China
* 63rd Institute of the Headquarters of General Staff,P.R.China


Abstract

In this paper, we first introduce the Generalised Polynomial Transform (GPT) and then establish various necessary and sufficient conditions for its existance. The polynomial transforms like FFT, FPT introduced by Nussbaumer and Quandalle, 1978; Nussbaumer, 1981; Reed, 1983; Pinneng Yu, 1994 are particular cases of GPT.

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GEOMORPHOMETRIC CHARACTERISTICS OF 30th SEPTEMBER 1993 KILLARI EARTHQUAKE AREA, MAHARASHTRA (INDIA)

R.D. Kaplay*, Md. Babar**, D.B. Panaskar* and A.M. Rakhe*
* School of Earth Sciences, S.R.T.M. University, Nanded
** Dept. of Geology, Dnyanopasak College, Parbhani

Abstract

Peninsular India has till recently been thought of as a stable region from seismic point of view. The strong earthquake that occurred at Killari on 30th Sept. 1993 has shattered this belief. The Deccan province is not as stable as was earlier believed. The reactivation of some faults in the basement beneath Deccan trap suggests that geological deformation is a continuous process. This is supported by geomorphological characteristics. The drainage pattern, straight courses of streams, sudden change in the path of the streams, offset drainage and morphometric factors like high variation of area ratio, high values of bifurcation ratio, notable difference in mean and weighted mean of bifurcation ratio, length ratio, and drainage density difference suggest that the geomorphology of the region is tectonically controlled and the structure has had an influence in the drainage development.

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