Low-frequency seismic spectrum measured by a laser interferometer combined with a low-frequency folded pendulum

摘要

A laser interferometer combined with a reference mirror suspended on a long-period folded pendulum is presented to measure the low-frequency horizontal seismic spectrum. One of the reflecting mirrors is driven by a piezoelectric transducer to track another mirror. The experimental results show that the horizontal seismic motion is about 10~(-9) m Hz~(-1/2) at 1 Hz in our laboratory.