1. Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Theresienstraße 41, D-80333 Munich, Germany
2. Victoria University of Wellington, School of Geography, Environment and Earth Sciences, Cotton Building, Gate 7 Kelburn Parade, Wellington 6012, New Zealand
3. Geophysics, Center for Earth System Research and Sustainability (CEN), Universität Hamburg, D-20146 Hamburg, Germany
4. Federal Institute for Geosciences and Natural Resources, Stilleweg 2, D-30655 Hannover, Germany