1 | I. Javakhishvili Tbilisi State University, Tbilisi, Georgia |
2 | I. Javakhishvili Tbilisi State University, E. Andronikashvili Institute of Physics, Tbilisi, Georgia |
3 | Joint Institute for Nuclear Research, Moscow Region, Russian Federation |
4 | Geophysical Observatory Borok, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences,
Yaroslavl Region, Russian Federation |