Abstract: A unique method has been developed which can show the presence of fractures in an Earth formation as a mappable attribute. This method uses the frequency spectra derived from P-wave seismic data over a pair of specific time windows above and below a seismic horizon or reflector of interest to infer the presence or absence of these geologic fractures based on an attenuation of high frequencies. The method produces a parameter value (t*) which is proportional to the shift in frequency spectra amplitudes (i.e., energy) from higher frequencies to lower frequencies, that is, from a time-window above a horizon or reflector of interest to a time-window below the horizon or reflector of interest.