This study investigates the application of a deflection detector to short-period seismic data. In general, for power detectors, no single filter will be optimal for a large variety of signals in a dynamic noise environment. The deflection detector represents an attempt to adapt to such a situation by utilizing individual FFT frequency cells as a bank of filters which can accommodate a broad variety of signals. The performance of the deflection detector is analyzed and compared to that of the power detector for several seismic signals. It is concluded that the deflection detector shows a distinct advantage when the variety of signal spectra to be detected is sufficiently large.