Intelligent Spatial-Clustering of Seismicity in the Vicinity of the Hellenic Seismic Arc

This research paper discusses possible seismic cluster formation and evolution in the vicinity of the Hellenic seismic arc and proposes a graphical user-interface monitoring and analysis tool based on various commercial and self-developed clustering algorithms for cluster discrimination, evolution and visualization. Self-developed algorithms enable the processing of both a) all recorder earthquakes and b) main seismic events alone, excluding foreshocks and aftershocks, by incorporating dynamic filters in space and time. The user can also import external formulae for the computation of the total earthquake preparation time, aftershocks duration and radius of the sphere of earthquake preparation region, and can also select specific regions of interest as well as the entire seismic map. The seismic imaging tool also addresses the concept of topical seismic cluster formation. Seismological maps indicate the presence of several seismic swarms forming within the region of the Hellenic arc, which appear to be either distinct or interacting together in groups of two or more. The identification of the number of possibly individual seismic clusters in a seismological area is a very challenging task by itself, which becomes even more complicated when investigating their outer boundaries especially in the case of multiple interacting clusters. The proposed imaging tool incorporates clustering algorithms that allow the user to apply various techniques for cluster identification, such as density based functions, gradient descent, centre of gravity, evolutionary allocation, and even import expert knowledge regarding the number of individual seismic clusters present.