1. Seismology and Physics of the Earth's Interior, Institute of Geophysics, Polish Academy of Sciences, Ks. Janusza 64, 01–452 Warsaw, Poland
2. Department of Earth Sciences, Uppsala University, Villavagen 16, 752 36 Uppsala, Sweden
3. Department of Geophysics, School of Geology, Aristotle University of Thessaloniki, GR54124 Thessaloniki, Greece