Observation of Earth Tides using a Laser Interferometer

The possibility of using a laser interferometer as a geophysical strainmeter was examined. A thermally stabilized laser was used and the results compared with a quartz Benioff strainmeter. From these measurements both long‐ and short‐term stability of the laser radiation were calculated. The results indicate that the long‐term stability is sufficient to observe earth tides while the short‐term stability is better than 1:1010.