1. Department of Physics University of Michigan Ann Arbor MI USA
2. Los Alamos National Laboratory Los Alamos NM USA
3. Mathematics and Computer Science Division Argonne National Laboratory Lemont IL USA
4. Department of Earth and Environmental Sciences University of Michigan Ann Arbor MI USA
5. Department of Civil and Environmental Engineering and Earth Sciences University of Notre Dame Notre Dame IN USA
6. Institute of Geodesy and Geoinformation University of Bonn Bonn Germany