Dynamic Foundation Investigation Roi-Namur, Kwajalein Atoll Marshall Islands,

Refraction seismic and vibration tests performed at the site of the proposed ALTAIR facility indicate the presence of two velocity zones. The upper zone showed an average compression wave velocity of about 1050 fps, a shear wave velocity of 575 fps, and a Poissons ratio of 0.29. The water table was at the 6-ft depth. Below the water table, to a depth of 24 ft, the average compression wave velocity, shear wave velocity, and Poissons ratio were about 4800 fps, 725 fps, and 0.49, respectively. Shear moduli increased normally for nonlayered materials. Seismic and vibration tests performed at the site of a proposed 48-in.-telescope foundation also indicated two velocity zones. Author