[1] Oregon Grad. Inst., Ctr. for Coast. and Land Margin Res., P.O. Box 91000, Portland,OR,97291-1000, United States
[2] Inst. for Hydromechanics, Univ. of Karlsruhe, Karlsruhe,D-76131, Germany
[3] School of Civ. and Envir. Engrg., Georgia Inst. of Technol., Atlanta,GA,30332, United States
[4] Ups Found. Visiting Prof., Dept. of Civ. Engrg., Stanford Univ., Stanford,CA,94305, United States