A description is given of a 15.1-m laser strainmeter installed in Katsiveli (Crimea), designed to record microdisplacements of the earth’s crust based on a device in the frequency range from zero (conditionally) to 1000 Hz with an accuracy of 0.1 nm. The main interference unit of the laser strainmeter is mounted on a concrete base rigidly connected to the upper layer of the earth’s crust, and the corner reflector is located on another concrete base, which is installed on a sand cushion. Between the main interference unit and the corner reflector, the beam of a frequency-stabilized helium–neon laser propagates along a sealed beam guide. A laser pressure variation meter is installed in the sea at a depth of 28 m and at a distance of 580 m from the laser strainmeter. It is designed to record changes in bottom hydrostatic pressure in the frequency range from zero (conditionally) to 1000 Hz with an accuracy of 13.5 mPa. All information obtained by these installations is sent via cable lines to the laboratory room, where, after preliminary processing, it is placed into the experimental database. The conducted synchronous testing of a laser strainmeter and a laser pressure variation meter demonstrated their great potential for studying vibrations and waves in the microseismic range.
Dolgikh et al. (Sun,) studied this question.