1. Formerly ETH Zurich, Institute of Geophysics, Department of Earth Sciences, Zurich, Switzerland; presently School of Geo-sciences and Info-Physics, Central South University, Hunan, China..
2. Formerly ETH Zurich, Institute of Geophysics, Department of Earth Sciences, Zurich, Switzerland, presently Uppsala University, Department of Earth Sciences, Uppsala, Sweden..
3. ETH Zurich, Institute of Geophysics, Department of Earth Sciences, Zurich, Switzerland..