Broadband Observation with Laser Strainmeters and a Strategy for High Resolution Long-term Strain Observation Based on Quantum Standard

摘要

Laser-interferometric strainmeters have several advantages over conventional quartz-tube and invar-rod strainmeters, such as high sensitivity, low drift, and expandability to long baseline measurements. Of these advantages, low-drift performance is the most significant if a frequency-stabilized laser is used as a light source for the strainmeter. Frequency stability reaches values better than 10 l!-10 l3; the potential strain accuracy of the laser strainmeter corresponds to these figures. Because strainmeters have a flat response to ground strain change, very broadband observations, such as earth tides, strain steps, and small earthquakes, with a range of 10"-10 Hz, are possible.