engleski

Mahalonobis clustering for the determination of incidence-magnitude seismic parameters for the Iberian Peninsula and the Republic of Croatia

The aim of this paper is to analyse the seismic activity of the Iberian Peninsula and a wide area of the Republic of Croatia. To do so, two incidence-magnitude seismic parameters have been defined. First, the areas have been divided into several ellipsoidal clusters using Mahalanobis clustering. Four generalised indexes (Mahalanobis Calinski Harabasz, Mahalanobis Davies–Bouldin, Mahalanobis Simplified Silhouette Width Criterion and Mahalanobis Area) have been used to determine the most appropriate number of ellipsoidal clusters, on the basis of which a partition with four and a partition with eleven clusters have been considered. For the wide area of the Republic of Croatia there are fourteen clusters and the five areas that just affect Croatia have been analysed in detail. Then, to analyse the seismic activity of the areas, two incidence-magnitude seismic parameters have been defined and calculated: a) Delta^{; ; (4)}; ; , that represents the minimal number of successive years in which at least one earthquake of magnitude between 4 and 5 has been registered ; b) Delta^{; ; (5)}; ; , that shows the number of years in which at least one earthquake of magnitude larger than 5 occurred. The calculation of Delta^{; ; (4)}; ; for the South- west and the South-east of the Iberian Peninsula has provided two years for both. Regarding Delta^{; ; (5)}; ; , 10 and 12 years have been obtained for the South-west and the South-east of the Iberian Peninsula, respectively. The analysis of Croatia has shown that the Ston–Metković area has the highest seismic activity. The following results have been determined: 5 years for Delta^{; ; (4)}; ; and 22 for Delta^{; ; (5)}; ; . It should be mentioned that these results cannot be used for predicting earthquakes. However, data about the incidences of earthquake events and their magnitudes can certainly serve as useful information in civil engineering.

Seismogenic zoning ; Adaptive Mahalonobis clustering ; Earthquake activity analysis

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