Mechanical energy has been used in the detection of shallow buried objects in granular beds for more than half a century. Here we attempt to answer a fundamental question - at what depths would an object be detectable in an idealized, close-packed, granular bed made of monosized elastic spheres? Systematic particle dynamics based studies reveal the effects of varying the area across which the impulse is generated, object size, and restitution on locating the buried object. © 2007 American Institute of Physics.