Analog analysis techniques have been applied to the long-period (peak response at 25 seconds period) strain and pendulum system at QCAZ (Queen Creek, Arizona). The purpose is to determine the effectiveness period P wave and Rayleigh wave signals from earthquakes. The long-period pendulum instruments at QCAZ are used as a standard for comparison. Outputs of the strain and pendulum seismographs are combined using an analog computer. The resultant output is then compared for a sample of forty-four earthquakes to the appropriate pendulum to establish signal-to-noise ratio gain (or loss). The lack of reduction of the rms noise amplitude is principally a result of strain system noise at periods greater than 16 seconds.