The probability of liquefaction in saturated sand deposits subjected to a train of shear stress pulses propagating from a point blast source applied at the boundary surface of the elastic medium is investigated. The load effect is evaluated in approximate closed form using three-dimensional tensorial mathematical physics in polar cylindrical coordinates. The adopted criterion of liquefaction has been experimentally verified both in the laboratory and in the field when continua of saturated sands were subjected to equivalent cyclic shear stress due to earthquake excitation. A first-order second-moment technique for the probabilistic assessment of the liquefaction potential in practical situations is developed and implemented in a computer program. Parametric studies are conducted to examine the sensitivity of results to the second-moment characterization of intervening key physical quantities.