Institution: | Department of Mathematical Sciences, Sweet Briar College, Sweet Briar, VA 24595-0142, USA. E-mail:;, Unitémixte de Recherche 6526 Géosciences Azur, Quai de la Darse—BP48, 06235 Villefranche-sur-mer cedex, France,;Division of Statistics, University of Virginia, Charlottesville, VA 22903, USA. E-mail:;, Department of Geology and Geophysics, Rice University MS126, Houston TX 77005, USA. E-mail: |