the invention relates to geophones and / or seismometers utilizing a casing housing a permanent magnet and a coil mass resiliently supported within the casing for movement relative to the permanent magnet along a primary axis , and wherein the mass is movably supported relative to the casing upon diaphragm springs utilizing involute spring elements . undesirable vibrational responses occurring in the diaphragm springs resulting from orthogonal forces are suppressed by partially filling the void within the casing with a damping fluid wherein the several involute spring elements of a spring are immersed or exposed to the damping fluid in varying degrees to damp resonant narrrow band orthogonal vibrations within the spring elements and permit accurate sensing along the primary axis over wide frequency ranges .