Figure 4: The three variation stages of the generalized dimension spectrum and singularity spectrum before 9 November 1996 Yellow Sea earthquake (M6.1). (a) and (d) show the generalized dimension spectrum and singularity spectrum two years prior to this earthquake, respectively; (b) and (e) show the generalized dimension spectrum and singularity spectrum seventeen months prior to this earthquake, respectively; (c) and (f) show the generalized dimension spectrum and singularity spectrum five months before this earthquake, respectively. The curve of the generalized dimension spectrum in Figure 4(b) is steeper than the two others, and the value range of the singularity spectrum in Figure 4(e) is broader than the two others. 
