Monitoring crustal vertical deformation by optical clocks network

Optical clocks with increasingly high accuracy have broadened scopes of applications of atomic clocks in scientific community as well as in life. One of the applications of optical clocks is based on the Einstein’s general relativity theory (GRT) to determine geopotential as well as orthometric height. The GRT concludes that a clock at a higher position (with a lower geopotential) will run faster than a clock at a lower position (with a higher geopotential). Therefore, relativistic geodesy has studied and come to the conclusion: using a clock with a stability of 10^-18, the height difference will be determined with an accuracy of 1 cm. Currently, optical clocks with a stability of 10^-19 have been created in the laboratory, which help scientists investigate prospective applications of the clocks in geodesy. One of the issues that scientists are interested in is monitoring the vertical deformation of the Earth's crust such as slow sliding events, earthquakes, volcanoes, etc. Here, we propose an optical clock network model for monitoring the vertical deformation of the Earth's crust. The optical clocks will be located at the fault layers and connected by fiber optic cables. The advantage of using a clock network over other classical methods (spirit leveling, GNSS) is that it is not only convenient and accurate (centimeter level or higher) but also not restricted by measurement time and geographic conditions. This study is supported by National Natural Science Foundation of China (NSFC) (grant Nos. 42030105, 41721003, 41631072, 41874023, 41804012), and Space Station Project (2020)228.

Key words: GRT, optical clocks network, orthometric height, crustal vertical deformation.