Abstract: In recent years, many fractal studies have been made in aspects of time, space, and intensity of earthquakes, but most of them are limited to single fractal (capacity dimension D₁ and information dimension D₂). It is found that single fractal is not enough to characterize the temporal and spatial fractal properties of earthquakes and commonly has a very narrow linear non-scale range. Moreover, single fractal dimensions cannot be obtained in some cases. In this paper, therefore, the correlation fractal dimension is adopted to analyze spatial characteristics of seismicity in Taiwan area. By use of plentiful earthquake records from the last century in Taiwan area, the correlation fractal dimensions for each seismic region, zone, and segment in this area are calculated, and then the fractal characterization for hypocentral distribution of earthquakes can be quantified. Finally, the relationship between the spatial correlation dimensions and the seismogenic environments in this area is construed synthetically. The major results are as follows: 1) the correlation fractal dimensions of the eastern seismic region of Taiwan area differs from that of the western region, owing to the different tectonic settings of the two regions; 2) each seismic region can be subdivided into different seismic zones based on the difference of plate tectonics, crustal structure and the distribution of active faults. Each zone has its distinctive correlation fractal dimension; 3) the different segments of each seismic zone have different characteristics of earthquake clustering, and hence have different correlation fractal dimensions. The results of this study indicate that there exists a good correlation between the spatial images of seismic activity obtained from correlation fractal dimension analysis and the corresponding seismo-tectonic settings.

Key words: correlation fractal dimension, tectonic setting, Taiwan area

摘要： 采用关联维方法对台湾地区地震活动的空间特征进行了研究.先利用100a来台湾的地震目录计算各个地震区、带的关联维数,将地震空间分布的分形特征定量表达出来,然后综合分析地震空间分布的关联维数和孕震构造环境之间的关系,得出了以下结论:1)台湾东、西部地震区由于地震属于不同的大地构造单元,因此关联维数有较大的差异;2)在各地震区内部的各个地震带由于板块构造、地壳结构、活断层分布上的差异,而具有与其构造特征相对应的关联维数;3)各地震带内部的各个不同的部位又由于不同的构造应力场,而导致地震分布上出现不同的丛集性,表现为不同的关联维数.这些结论充分说明通过关联维分析所得到的地震活动的空间图像与地震活动所代表的不同地质构造背景有着良好的对应关系.

关键词: 关联维, 构造背景, 台湾地区