Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

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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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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D. Purushotham ¹, A. Narsing Rao ², M. Ravi Prakash ¹, Shakeel Ahmed ¹, G. Ashok Babu ¹

Affiliations
1 National Geophysical Research Institute, Hyderabad - 500 007, IN
2 Geology Department, Osmania University, Hyderabad - 500 007, IN

Abstract

Maheshwaram watershed is situated in Ranga Reddy district of at a distance of about 30 km south of Hyderabad. The watershed has an area of 53 km² and has hard rock aquifers with semi-arid climate. The study area has been expanding at a fast pace and now has the distinction of being one of the fastest growing urban centers, facing the problem of groundwater depletion and quality deterioration due to the absence of perennial source of surface water and also due to over exploitation. Human activities involving industrial and agricultural development and the inadequate management of land and water resources have, directly or indirectly resulted in the degradation of environment viz. water and soil.

In the present study chemical analysis of groundwater samples of the study area, collected in pre- and post-monsoon has been carried out. The analysed data is utilized to characterize the hydro chemical process dominant in the area. Various classification methods such as Piper, Back and Hanshaw, Wilcox, U.S. Salinity Laboratory are employed to critically study the geochemical characteristics of groundwater.

Keywords

Groundwater, Geochemistry, Anthropogenic, Environment, Watershed, Maheshwaram, Andhra Pradesh.

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