1. Division of Engineering and Applied Science, Dept. of Mechanical and Civil Engineering, California Institute of Technology, Pasadena, CA.
2. Division of Engineering and Applied Science, Dept. of Mechanical and Civil Engineering, California Institute of Technology, Pasadena, CA
3. US Geological Survey, Pasadena, CA
4. Dept. of Engineering Civil, Environmental, and Geodetic Engineering, Ohio State Univ., Columbus, OH