July, 2007

July, 2007   ||  Volume 11 No.3

A note on the qualitative appraisal of aeromagnetic image of Chhattisgarh basin

B. Ram, N.P.Singh and A.S.K.Murthy

Department of Geophysics, Banaras Hindu University, Varanasi – 221 005

Email: drbram_bhu@yahoo.co.in, singhnpbhu@yahoo.co.in, draskm_bhu@yahoo.com

Qualitative appraisal of aeromagnetic image of Chhattisgarh region has been carried out to study the geology of the region. The study area comprises of Chhattisgarh basin, one of the seven-purana basins of Peninsular India. The aeromagnetic anomaly map of the area has been used as input for interpretation to extract the geologic information from the mapped and imaged anomalies in a systematic way that makes a positive contribution to the geology of the area. On the basis of aeromagnetic anomalies, Chhattisgarh basin can be divided into the northern low anomaly zone and the southern high anomaly zone. The northern portion of the main Chhattisgarh basin has been further divided into two sub-basins namely Hirri sub-basin (HRSB) in the west and Baradwar sub-basin (BRSB) in the east by NW-SE trending Sonakhan greenstone belt with maximum negative amplitude. The positive magnetic anomaly zone east of 81.50 E and bounded by 19.50 and 21.00 N latitude is due to Dongargarh granites and their equivalents. The greenstone belt, Dongargarh granite, granulites/gneisses occurrences in the region and intrusive bodies are clearly demarcated in the inferred geological map.


Estimation of permeability of shaly sand from induced polarization relaxation time spectra
Vikas Saluja and Sri Niwas

Department of Earth Sciences, Indian Institute of Technology,

Roorkee – 247 667

E.mail : vikaspes@yahoo.com

The Singular Value Decomposition (SVD) method is used to invert induced polarization (IP) decay curve for the IP relaxation time spectrum. A nonnegative restriction is added during inversion for meaningful solution of the amplitude of the relaxation spectrum. The analysis of the experiment design, by comparing results in different range, shows that the appropriate number of relaxation arrangement points in data inversion lies with 32 to 64. The attenuation of noise in this range is better and resolution is good. IP relaxation spectrum indicates the pore size distribution that in turn indicates the permeability of shaly sand reservoir. Combining the average relaxation time (geometric average time) with the porosity can improve the accuracy of estimation of the permeability in comparison to that obtained using total porosity from core measurements.

Energy Attenuation of Sea Surface Waves through Generation of Interface Waves on Visco-elastic Bottom as in the Mud Banks, SW Coast of India

S.Minirani and P.G.Kurup1
School of Marine Sciences, Cochin – 682 016

1Amrita School of Arts and Sciences, Brahmastanam, Cochin – 682 024

E.mail ; kuruppg@yahoo.co.uk

The mud banks present picturesque instances of large- scale natural damping of sea surface waves. When waves propagate on the surface of a layer of inviscid fluid overlying a visco-elastic bottom fluid of greater density, surface wave energy is dissipated by the coupling between the surface wave sand the waves generated at the interface. Using a dimensionally correct expression (Mac Phersonand Kurup, 1981) obtained from Gade’s mathematical model (1958), the wave energy attenuation is calculated for different wave periods, water depths and fluid layer thickness. The predicted wave decays are comparable to those observed in the mud banks where the seabed is of soft viscous mud. The waves get almost completely attenuated over a distance of 5-10 wavelengths.

RF Emissions, Types Of Earthquake Precursors: Possibly Caused By The Planetary Alignments
Seismology Division, Bhabha Atomic Research Centre, Trombay,

Mumbai 400 08

5Email: vkolvankar@yahoo.com

Various research workers have reported EM emission prior to earthquakes or during an earthquake sequence. In few cases, these EM emissions were consistently found during certain hours of the day. EM emission in semi-diurnal pattern spaced in time domain from the local noontime was observed in many examples prior to earthquakes / volcanic eruption. Also such emission was observed in a very wide frequency band from VLF to Microwave range. Besides this semi diurnal type of pattern, some other type of EM emission had diurnal pattern. This type was witnessed in Valsad [1991] and Chilean earthquake sequence [1960], in which it preceded semidiurnal pattern found in these earthquake sequences. The cause of this type of EM emission seems to be completely different than that for semidiurnal type. Efforts are made here to check whether the gravitational forces of the planetary alignments caused these types of RF emission. This paper discusses all these examples in details and discusses an application for the development of reliable monitoring of Earthquake/ Volcanic eruption precursors in the high seismicity area.



Development of SMS-based G2I System to Generate Reference GIS Maps for Real Time Vehicle Tracking Applications
D.Krishna Reddy, A.D.Sarma1, Sreenivasa R.Pammi1 and M.V.S.N.Prasad2

Chaitanya Bharathi Institute of Technology, Hyderabad

1R & T Unit for Navigational Electronics, Osmania University,

Hyderabad, India.

2Radio and Atmospheric Science Division, National Physical Laboratory, New Delhi, India.

E-mail: dkreddi@rediffmail.com, ad_sarma@yahoo.com

In this paper details of development and applications of a navigation system known as GPS-GSM Integrator (G2I) are presented. G2I system consists of two modules namely In Vehicle Module (IVM) and Control Room Module (CRM). The IVM is micro controller based system equipped with Global Positioning System (GPS) receiver and Global System for Mobile communication (GSM) modem. The CRM consists of a Personal Computer (PC) and GSM mobile phone. Relevant software is developed for obtaining position information of vehicle. Drive tests are conducted with G2I system (in different modes) for cellular coverage area determination and for developing comprehensive digital reference Geographical Information System (GIS) maps in real time vehicle tracking. During these tests, the Received Signal Strength Indications (RSSI) of the cellular signal at various locations (latitude and longitude) in urban and rural regions are recorded and coverage area classification isdone. The developed G2I system would be helpful for implementation of Location Based Services (LBS) of Third Generation (3G) communications.




Geo-tectonic movement and natural hazards: Strategy for disaster preparedness and mitigation

R.D.Singh and Purnima Singh1

Department of Regional Planning and Economic Growth and Environmental Management Programme at

The Centre for The Study of Environment and Sustainable Development, Barkatullah University, Bhopal - 462026

1Sarojini Naidu Government Girls College, Bhopal.

E-mail: rd_singh 54@yahoo.com

In India, the incidence of natural hazards have increased in recent times and their intensity and impacts have increased. Though the natural hazards like earthquake in Indian sub-continent cannot be prevented, because of the active tectonic disturbances and resulting incidence of earthquake of different intensities in sensitive zones, with a better preparedness and mitigation plan, the loss of ife and property can be minimised to a greater extent. Though the scientific and technological knowledge is available for disaster preparedness and mitigation in different disaster prone regions of the world, the lack of disaster management system in disaster prone regions is causing collateral damages causing enormous environmental costs in form of loss of life and property and the cost of rehabilitation. The neglect of the development of disaster management system for minimisation of the impact of such disasters have caused a huge cost, even a fraction of which could help in disaster management capacity building in disaster prone regions. This paper identifies the regional pattern of disaster sensitive zones, the causal relation of tectonic movement on sismicity and resultant cummulative impacts of earthquake, landsliding, changes in landforms and meandering of rivers causing floods and other cummulative human interface. On the basis of such analysis, the model framework is suggested for disaster preparedness and mitigation plan in the sensitive zones.