1. School of Geology, Department of Geophysics, Geophysical Laboratory, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
2. Department of Statistics and Actuarial-Financial Mathematics, Lab of Statistics and Data Analysis, University of the Aegean, 83200 Samos, Greece
3. Department of Computer Science, University of Nicosia, Nicosia 2417, Cyprus
4. Department of Statistics and Insurance Science, University of Piraeus, 18534 Piraeus, Greece
5. Department of Mathematics, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
6. National Observatory of Athens, Institute of Geodynamics, Lofos Nymfon, Thissio, 11851 Athens, Greece