The Fractal Nature of the Earth: Redefining Geophysical Interpretation

Sources of geophysical anomalies, such as density, susceptibility, conductivity, reflectivity, etc., are not always random as we often assume, but follow a scaling/fractal distribution. This has been demonstrated by analyzing borehole data from the German Continental Deep Drilling Programme (KTB) and other boreholes used for oil exploration. The new scaling spectral method (SSM) was developed to interpret gravity, magnetic, resistivity, and other geophysical measurements, which are better than the conventional spectral method. The application of fractal and scaling approaches in Earth science is widespread across all aspects of geophysics, including the acquisition, processing, and interpretation of geophysical data. The selection criteria for spacing for measurement stations in a 1D survey or grid size for a 2D survey have been suggested. Similarly, processing of non-stationary data is subdivided into stationary data for which the SSM can be applied. Potential field theory has also been studied in the context of fractals or scaling laws and has been found to be worthwhile in inferring the physical properties of the subsurface. The Voronoi tessellation approach using fractional dimension has been applied to model the subsurface from field geophysical data. Here, an attempt is made to discuss the in-depth review of the application of the fractal/scaling approach for qualitative and quantitative interpretation of complex sources of interest. The implications of this study will be beneficial for readers, enabling them to understand the gaps in subsurface source characterization, with practical applications demonstrated through field geophysical examples.