University of California Berkeley, Civil and Environmental Eng. 413 Davis Hall, Berkeley, CA 94720-1710, United States ; Oviedo University, Dpt. Matematicas C/Calvo Sotelo S/N, Oviedo, Ast 33006, Spain
Oviedo University, Dpt. de Explotacion y Prospeccion de Minas. C/ Independencia, Oviedo, Ast 33001, Spain
University of California Berkeley, Civil and Environmental Eng. 413 Davis Hall, Berkeley, CA 94720-1710, United States