The Fractal Dimensionality of Seismic Wave

As a new nonlinear science, fractal theory is investigated and applied widely in many complex fields, such as seismology. Today there have been many research results to prove that seismic waves have fractal characteristics, while the influence and significance of the fractal is neglected calculating earthquake action of practical engineering design. Seismic wave is fractal time series data, and the fractal dimensionality of it is a magnitude which can characterize the degree of the data enriching the time amplitude plane. In this paper, it was pointed out that the fractal dimensionality value also should be as one of the parameters of the seismic waves from researching on the design response spectrum curve. Using an improved ‘box counting method’, this study was carried out to calculate fractal dimensionalities of a set of famous ground motion records in different site conditions and basic intensities. And some characteristics of fractal dimensionalities were introduced though contrasting and analyzing. Furthermore, four influencing factors were illustrated, which can impact the magnitudes of fractal dimensionalities of seismic waves.