[1] Hungarian Acad Sci, Dept Met Res, Res Inst Solid Phys & Opt, Budapest, Hungary
[2] Eotvos Lorand Univ, Lithosphere Fluid Res Grp, Budapest, Hungary
[3] Free Univ Berlin, D-1000 Berlin, Germany
[4] Eotvos Lorand Geophys Inst Hungary, Budapest, Hungary
[5] Univ Bayreuth, Bayer Geoinst, D-8580 Bayreuth, Germany
[6] Helmholtz Ctr Potsdam, GFZ German Res Ctr Geosci, Potsdam, Germany