Many manufacturers of blasting seismographs supply their transducers with spikes and
recommend using them. Spikes can be effective for ground accelerations less than 1.0 g
(ISEE, 2005; Stagg and Engler, 1980) though Dowding (1992) specifically discourages the
use of spikes since they may affect the response of the recorded motion. Blair (1995a) has
reported that spiked mounting over-estimated the true ground vibration by 46.5% on the
average and proposed a pre-cast mount embedded in soil (Blair, 1995b). It may be noted that
spiked mount does not have to be decoupled to be poor.