1. Department of Geoscience; University of Calgary; Calgary, Alberta; Canada
2. Institute for Geophysics and Department of Geological Sciences; Jackson School of Geosciences, University of Texas at Austin; Austin; Texas; USA
3. Department of Earth and Environmental Sciences; University of Rochester; Rochester; New York; USA
4. Department of Earth Sciences; California State University Dominguez Hills; Carson; California; USA
5. Department of Geological and Environmental Sciences; Stanford University; Stanford; California; USA