1. U.S. Geological Survey, Lubbock Field Office, Science Building MS-1053, Texas Tech Univ., 2500 Broadway, Lubbock, TX 79409 (corresponding author).
2. Research Associate, Dept. of Civil and Environmental Engineering, Texas Tech Univ., CEE Building MS-1023, Lubbock, TX 79409; and Retired, Texas Dept. of Transportation. Austin, TX 78701.
3. Dept. of Civil and Environmental Engineering, Texas Tech Univ., CEE Building MS-1023, Lubbock, TX 79409.