Fig. 1.

Multivariate normal mixture model clustering results of the Tamba area. Figure 1(a): The left picture shows the locations of historical earthquakes. The different symbols, squares, circles, triangles, inverted triangles, asterisks and diamonds show the assignment of each earthquake to one of the six clusters. The standard deviation of each cluster is shown by an ellipsoid. The mean of each cluster is shown as a cross. Figure 1(b): The right picture shows the log transformed density of the area as estimated by Eq. (1). The contours represent increasing density.