Aiming at the complexity of seismic gestation mechanism and spatial distribution, we hypothesize that the seismic data are composed of background earthquakes and anomaly earthquakes in a certain temporal-spatial scope. Also the background earthquakes and anomaly earthquakes both satisfy the 2-D Poisson process of different parameters respectively. In the paper, the concept of N-th order distance is introduced in order to transform 2-D superimposed Poisson process into 1-D mixture density function. On the basis of choosing the distance, mixture density function is decomposed to recognize the anomaly earthquakes through genetic algorithm. Combined with the temporal scanning of C value, the algorithm is applied to the recognition on spatial pattern of foreshock anomalies by exam-ples of Songpan and Longling sequences in the southwest of China.
土壤侵蚀作为一个全球性的环境问题已经越来越受到人们的广泛关注。动态模拟和预测土壤侵蚀的发育及演化过程具有十分重要的意义。元胞自动机(C e llu lar A u tom ata简称CA)是一种“自下而上”的动态模拟建模框架,具有模拟地理复杂系统时空演化过程的能力。从元胞自动机的概念和原理入手,介绍了CA模型的特征及其在土壤侵蚀学科中的应用情况和存在问题,对CA模型应用于土壤侵蚀过程的模拟、预测的可行性和可操作性进行了探讨。
