One year of operation of laser inclinometers in Kamchatka: one step closer to earthquake prediction
One year of operation of two inclinometers installed 5.6 km apart in different parts of Petropavlovsk-Kamchatsky has come to the end. The inclinometers synchronically detected microseismic events. The uniqueness of these devices is their ability to detect angular changes of the Earth surface with the unprecedented accuracy of 10 nrad, which is 100 times higher than the accuracy of traditional devices.
The maintenance of inclinometers included oil change in its cuvette with further adjustment and calibration and check of remote data transmission.
The results of the one-year measurements are the following:
– The effect of irreversible change in the angular position of the Earth surface after large earthquakes is detected. For example, the 7.0 magnitude earthquake caused a change in the inclination of the surface of about three microradians, which was clearly detected by the inclinometer.
– The first data about free oscillations of the Earth with a distinctive amplitude of only 10 nrad.
– Time synchronization of inclinometers enables the creation of a “video” of landscape changes. It may help to discover zones of seismic energy accumulation and to detect earthquake forerunners such as absorption of the Earth free oscillations in places where crust faults are formed.
These results are at the publication stage for now.
Mikhail Lyablin held two seminars in the Institute of Cosmophysical Research and Radio Wave Propagation of the Far Eastern Branch of the Russian Academy of Sciences and Kamchatka branch of the Geophysical Survey of the Russian Academy of Sciences. The seminars were devoted to presentation of an angular interferometer and its application in inclinometers of the next generation.
The new type of angular interferometer will allow significantly decreasing overall dimensions and coming closer to the implementation of the project of submersible inclinometer that is less than 9 cm in diameter. It will give an opportunity to install such inclinometers in trial pits and take measures of physical inclinations of the Earth surface in solid rock.
Both seminars were met with great interest from the viewpoint of the possibility of detecting low-frequency angular movements of the Earth’s surface. Such a net will allow discovering zones of seismic energy accumulation.