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M. Ravi Prakash ¹, V. P. Dimri ¹

Affiliations
1 National Geophysical Research Institute, Hyderabad -500 007, IN

Abstract

Fractal dimensional analysis has been carried out on the aftershock sequence of the Latur earthquake (M_L 6.3) of September 30, 1993. Both the spatial and temporal correlation dimensions exhibit monofractal property. The spatial correlation dimension is found to be 1.75 indicating that the events tend to propagate in the whole region. The temporal correlation dimension is found to be 0.55 representing a non-continuous activity. The b-value obtained from the magnitude-frequency relation is found to be 0.56, which is typical of SCR seismicity. The focal depth-frequency analysis of the aftershocks showed that the lower boundary of the aftershock depth is about 7 km. The shallow depth of foci is a typical characteristic of the SCR seimicity. The fractal dimension obtained from the b-value is 1.12, which is close to 1, and reflects the 'stable state' of the system and confirms that the main event belongs to SCR. The frequency-time distribution analysis of the aftershocks indicated that the earthquake generation process is not random. The parameter 'p' of the modified Omori's formula for aftershock frequencies is estimated at 0.22.

Keywords

Earthquake, Stable Continental Region, Aftershock, Omori's Law, Fractal Approach, Latur, Maharashtra.

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V. P. Dimri ¹

Affiliations
1 National Geophysical Research Institute, Hyderabad 500 007, IN

Abstract

No Abstract.

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Lukman A. Sunmonu ¹, V. P. Dimri ²

Affiliations
1 Department of Pure and Applied Physics, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, NG
2 Fractals in Geophysics Group, National Geophysical Research Institute, Hyderabad - 500 007, IN

Abstract

Northeast India experienced compressive forces from the Himalayan Arc in the north and the Burmese Arc in the east, which led to the development of a number of seismogenic faults, fractures and lineaments. It is observed that the characteristics of earthquakes occurring on an active fault are closely related to the irregularity of fault geometry. Because of their rough appearances over many length scales, faults can be conveniently regarded a. fractal sets, and their georretrical irregularity can be quantified using fractal dimension. We have calculated fractal dimension of the distribution of faults in two tectonic blocks, Bengal basin and Tripura fold belt, in the northeast India. We found that in the spatial sense the fractal dimension and the seismicity are positively correlated.

Keywords

Earthquake, Seismicity, Fractal Dimension, Faults, Tripura, Bengal Basin, Ne India.

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Harsh Gupta ¹, D. Shashidhar ¹, Metilda Pereira ¹, N. Purnachandh Roa ¹, M. Kousalya ¹, H. V. S. Satyanarayana ¹, Satish Saha ¹, R. T. Babu Naik ¹, V. P. Dimri ¹

Affiliations
1 National Geophysical Research Institute, Uppal Road, Hyderabad -500007, IN

Abstract

No Abstract.

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A. R. Bansal ¹, V. P. Dimri ¹, G. V. Sagar ¹

Affiliations
1 National Geophysical Research Institute, Uppal Road, Hyderabad - 500 007, IN

Abstract

In frequency domain, interpretation of gravity and magnetic measurements was carried out by the spectral method and its variants. The spectral method assumes the source distribution as white noise. Whereas the detailed analysts of borehole data from several areas reveal that physical properties such as density, susceptibility reflectivity sequences etc follow a scaling distribution. The scaling distribution of sources is incorporated in spectral method and the new approach is known as the scaling spectral method. This method is applied to the gravity and magnetic data of Kuppam-Palani geotransect in southern granulites of southern India. The depth values calculated for the Kuppam- Palani transect agree well with the seismic study. The deviation in the value of the scaling exponent for Mid-crustal layer shows the differing nature of the crust for Kuppam-Bhavani and Kolattur-Palani sections of the Kuppam-Palani transect. Further, different values of scaling exponent obtainable from gravity and magnetic data for the same depth indicate that sources for gravity and magnetic anomalies are different.

Keywords

Scaling Spectral Method, Scaling Exponent, Gravity And Magnetic Methods, Southern Granulite Terrain, Kuppam-Palani Transect.

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Harsh Gupta ¹, D. Shashidhar ¹, Metilda Periera ¹, Prantik Mandal ¹, V. P. Dimri ¹

Affiliations
1 National Geophysical Research Institute, Hyderabad - 500 007, IN

Abstract

No Abstract.

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S. Chandra ¹, S. Atal ¹, N. S. Krishnamurthy ¹, k. Subrahmanyam ¹, R. Rangarajan ¹, D. V. Reddy ¹, P. Nagbhushanam ¹, J. V. S. Murthy ¹, S. Ahmed ¹, V. P. Dimri ¹

Affiliations
1 National Geophysical Research Institute, Hyderabad - 500 007, IN

Abstract

No Abstract.

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P. S. Raju ¹, R. V. Raghavan ¹, E. Umadevi ¹, D. Shashidar ¹, A. N. S. Sarma ¹, D. Gurunath ¹, H. V. S. Satyanarayana ¹, T. Sagara Rao ¹, R. T. Babu Naik ¹, N. Purnachandra Rao ¹, M. D. Kamuruddin ¹, U. Gowri Shankar ¹, N. K. Gogi ¹, B. C. Baruah ¹, N. K. Bora ¹, M. Kousalya ¹, M. Sekhar ¹, V. P. Dimri ¹

Affiliations
1 National Geophysical Research Institute, Uppal Road, Hyderabad - 560 007, IN

Abstract

No Abstract.

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Ravi Prakash Srivastava ¹, Sandip Chattopadhyay ¹, Nimisha Vedanti ¹, V. P. Dimri ¹

Affiliations
1 Fractals in Geophysics Group, National Geophysical Research Institute, Uppal Road, Hyderabad - 500007, IN

Abstract

Gravity and total field magnetic intensity data have been collected over three adjacent circular geomorphic features near Jabalpur, presently reported as volcanic vents in the Deccan volcanic province. Bouguer anomaly variation of the order of 1.2 to 2 mGal in a 1.5 km long profile, and total field magnetic anomaly of the order of -900 to 1400 nT have been observed. The gravity variation does not give any reflection of underlying deep seated high density material; and there are no isolated or elliptical magnetic anomalies that can be attributed to the presence of deep seated anomalous source like a volcanic vent. The basement depth values as determined by Werner deconvolution technique corresponding to the three circular geomorphic features is 51.7, 57.6 and 75 m.

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Lukman A. Sunmonu ¹, V. P. Dimri ¹, M. Ravi Prakash ², Abhey Ram Bansal ²

Affiliations
1 Department of Pure & Applied Physics, Ladoke Akintola University of Technology, P.M.B. 4000 Ogbomoso Oyo State, NG
2 Fractals in Geophysics Group, National Geophysical Research Institute, Hyderabad - 500 007, IN

Abstract

We presented time series analysis of multifractal properties of M≥7.0 earthquakes in Himalaya and vicinity during the period 1895-1995. The multifractal analysis of complex phenomena involves the estimation and interpretation of D_q-q relation. Our investigations show that: (1) the distribution of earthquakes of M≥7.0 on the time axis has a multifractal set, (2) well distributed, steep type decreasing function of D_q with increasing q, indicates high rates of accumulation and release; therefore, leading to adjustment of a large scale stress field in the area, and (3) value of D₂ = 0.95 > D₂ > D_∞ = 0.80.

Keywords

Multifractal, Time Series, Earthquake, Himalaya.

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V. P. Dimri ¹, Anand K. Pandey ¹

Affiliations
1 CSIR-National Geophysical Research Institute, Uppal Road, Hyderabad 500 007, IN

Abstract

No Abstract.

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Ravi P. Srivastava ¹, Nimisha Vedanti ¹, O. P. Pandey ¹, V. P. Dimri ¹

Affiliations
1 National Geophysical Research Institute, (Council of Scientific and Industrial Research), Hyderabad - 500 007, IN

Abstract

Vindhyan Basin of Central India situated just north of SONATA rift zone, forms one of the major geotectonic segment of the Indian subcontinent which is associated with complex thermo-tectonic history. Southern part of this basin is known to contain favorable conditions for hydrocarbon entrapment. Keeping this in view, a detailed gravity survey network comprising 40 gravity bases and 1500 data points in an area of about 110 × 100 km² was planned in and around Jabera-Damoh region. Analysis of Bouguer and free air gravity anomaly maps, prepared using fractal based gridding method, indicates presence of two sedimentary basins (Jabera and Damoh) faulted on either sides beside ridge like features. However, well-known Jabera domal structure appeared to be a shallow feature only. Inversion of gravity data further reveals presence of 5 to 6 km thick Vindhyan sediments in the Jabera basin which are underlain by Mahakoshal/ Bijawar group of rocks, resting directly over the lower crust, thereby indicating almost total absence of granitic crust from this region. It appears that due to an underlying thermal anomaly, the entire region may have been subjected to sustained uplift, deformation, erosion and consequent crustal extension during early to mid Proterozoics which brought high velocity mafic crust to such shallow levels.

Keywords

Gravity Studies, Crustal Evolution, Lower Crust, Fractals, Gravity Data Inversion, Vindhyan Basin.

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S. P. Singh ¹, M. Sanwal ², V. P. Dimri ³, S. K. Dubey ⁴

Affiliations
1 Lives at 195-Phase I, Vasant Vihar, Dehradun 248 006, IN
2 Lives at House No. 204, Sector 15A, Noida 201 301, IN
3 University of Hyderabad, Hyderabad 500 007, IN
4 Lives at A-30C, DDA Flats, Munirka, New Delhi 110 067, IN

Abstract

We analyse here achievements of DST’s Climate Change Programme run by a small team of science administrators. The programme was run in a campaign mode in which DST science administrators not only made several young scientists interested in the programme, but also played a role of co-partner in developing the project concept and plans. The main features of the programme are: (i) several young scientists have taken lead role in carrying out research in climate change; (ii) creation of research networks; (iii) a remarkable rise in quality research papers; (iv) training of over 35,000 personnel, and (v) a marked change in the style of running a programme in which DST science administrators, committee members and researchers worked together with more trust and understanding, involving frequent interactions.

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