Systems are disclosed for securing near vertically deployed seismic detector systems in a cased well borehole from oscillatory motion during a seismic survey. In one embodiment a generally cylindrical body member of an unsymmetrical shape having one flat side is used opposite a selectably extensible backup locking arm. In a second embodiment a generally symmetrical cylindrical body member having sets of four essentially coplanar contacting feet disposed at 90 degree circumferential spacing an opposite ends is provided. The sets of locking feet on opposite ends of the tool body member are phased 45 degrees apart circumferentially with respect to each other. Locking edges and feet may be magnetically assisted if desired.