HR: 14:55h
AN: NG23A-01    [Abstracts]
TI: Role of Fractals in Solid Earth Geophysics
AU: * Dimri, V P
EM: vpdimri@ngri.res.in
AF: National Geophysical Research Institute, Uppal Road, Hyderabad, AP 500007, India
AB: Various studies carried out across the globe reveal that many of the Earth's processes satisfy fractal statistics, where examples range from the frequency-size statistics of earthquakes to the time series of the Earth's magnetic field. The scaling property of fractal signal is very much appealing for descriptions of many geological features. It is observed from the German Continental Deep Drilling Programme (KTB) and many other deep bore wells around the world that the source distribution of density, magnetic susceptibility, electrical conductivity, acoustic impedance etc. follows power-law, hence they are fractal in nature. This finding has been incorporated in various geophysical techniques to better understand the non-linear processes in Earth systems. Theoretical relation between source and potential fields is established and based on that techniques for gravity and magnetic interpretation methods have been reformulated. A new scaling power spectral method is developed to understand source behaviour and parameters of the Earth's interior. Further, fractal concept of tessellation has been used to model the complex geometrical object, which was hitherto unaddressed. An entirely new technique has been proposed to generate the complex geometrical structures with desired physical property variation for forward and inverse modeling of the geophysical data. Further, the concept of fractal distribution of frequency and magnitude of earthquakes is exploited in aftershock study of the major earthquakes such as, Uttarkashi (1991), Latur (1993), Jabalpur (1997), Chamoli (1999), Bhuj (2001) and Muzzafarabad (2005). This study revealed that the Himalayan earthquakes follow multifractal distribution however, shield earthquakes follow monofractal distribution. This finding has been used to explain the earthquake mechanism in Himalayan and shield areas. The fractal study was extended to sea earthquakes and wave propagation modeling is done to understand the effect of Tsunami generating earthquakes from Makran and Sumatra subduction zones in Arabian Sea and Bay of Bengal respectively of Indian Ocean.
DE: 4400 NONLINEAR GEOPHYSICS (3200, 6944, 7839)
DE: 4440 Fractals and multifractals
DE: 4475 Scaling: spatial and temporal (1872, 3270, 4277)
DE: 4499 General or miscellaneous
SC: Nonlinear Geophysics [NG]
MN: 2007 Fall Meeting