A fast partitioning algorithm and its application to earthquake investigation

In this paper a new fast partitioning algorithm able to find either a globally optimal partition or a locally optimal partition of the set A ⊂ R close to the global one is proposed. The performance of the algorithm in terms of CPU time shows significant improvement in comparison with other incremental algorithms. Since optimal partitions with 2, 3, . . . clusters are determined successively in the algorithm, it is possible to calculate corresponding clustering validity indexes for every number of clusters in a partition. In that way the algorithm also proposes the appropriate number of clusters in a partition. The algorithm is illustrated and tested on several synthetic and seismic activity data from a wider area of the Republic of Croatia in order to locate the most intense seismic activity in the observed area.