1. Institute for Geosciences, Kiel University, 24118 Kiel, Germany
2. Department of Informatics, Bioengineering, Robotics and Systems Engineering (DIBRIS), University of Genoa, Via Dodecaneso, 35, 16146 Genoa, Italy
3. Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON N2L 3G1, Canada