Exploring potential applications of optical lattice clocks in a plate subduction zone

Abstract Optical clocks improved the accuracy of state-of-the-art cesium by more than two orders magnitude and enabled frequency comparison with a fractional uncertainty one part in 10 18 . Gravitational redshift such allows determining their height difference an 1 cm. In Europe, chronometric leveling has been extensively conducted for unifying reference systems. Temporal response leveling, which affords monitoring cm variation within hours averaging time, may offer new opportunities to explore seismology volcanology. Superb stability optical lattice will be best used applications. This article outlines prospects Japan. Combining existing observation network GNSS, crustal deformations monitored unprecedented future.