1. Department of Physics, Technion – Israel Institute of Technology , Technion City, 3200003 Haifa, Israel
2. School of the Environment and Earth Sciences, Tel Aviv University , Ramat Aviv, 6997801 Tel Aviv, Israel
3. Institute for Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig , Mendelssohnstr. 3, D-38106 Braunschweig, Germany