Monitoring System of Seismo Dynamics of Rocks for Recording Earthquake Precursors

Internet of things (IoT) and smart city technologies are closely related to citizen security issues. One of the important components of safety is to reduce damage from man-made and natural disasters. In this area, the most important direction is the continuous monitoring of rock vibrations under the influence of tidal forces. These technologies, with minor changes, can be used to monitor the state of complex technological structures, such as dams, bridges, large buildings. It is known that continuous recording of micro deformations of rocks under the action of gravitational forces from the Sun and the Moon due to a change in their location in relation to the Earth's surface allows one to obtain additional information about the possible future earthquakes. The corresponding meters are based on two helium-neon (He-Ne) lasers. They contain a rather complicated and insufficiently reliable system for automatic phase and frequency tuning of the slave laser to the master. Insufficient accuracy of such phase feedback control generates errors in measurement. This paper proposes to abandon such variants of the devices based on the use of two lasers. The structure based on the only laser has been proposed. This requires metrological justification, as well as the development of appropriate optical schemes, design development and change of the electronic part. Nevertheless, such a modification seems appropriate. The reasons for this lie in a clear increase in reliability and accuracy, a decrease in cost and size.