地震多重分形计算的最小生成树法

THE MINIMAL SPANNING TREE METHOD FOR CALCU-LATING SEISMIC MULTI-FRACTAL

目前地震分形计算的方法很多 ,但各方法或多或少都存在一些问题 .本文引入一种地震分形计算的新方法最小生成树法 ( minimal spanning tree) ,对其算法作了重要的修改 ,并通过对乌什、乌苏、唐山和海城 4个区域震例的研究 ,得出大震前后地震时空分布多重分形谱由集中变疏张 ,反映了分形结构复杂性的增加、地震时空分布不均匀性的增加 .由点集的数值模拟表明 :强震前后多重分形谱变化的物理本质是地震分布由均一到不均一 。

WT5BZ]There are many methods to calculate seismic fractal at present. However, there are still more or less questions to every method. In this paper, we introduce a new way to calculate seismic fractalthe minimal spanning tree. We make an important improvement for this method. By studying some seismic events of four regions including Wushi, Wusu, Tangshan and Haicheng, we obtain that, before the strong earthquake occurrence, the multi fractal spectrum of the space time distribution of earthquakes changes from centralized to loose. The result shows that the complexity of fractal structure and the inhomogeneity of the space time distribution of earthquakes are both increasing. By studying the numerical simulation of point sets, we draw the conclusion that the physical essence of multi fractal spectrums before and after a strong earthquake occurrence is a changing process from homogeneous to inhomogeneous, from simple to complex.