Abstract

CHRONOS (Cryogenic sub-Hz cROss torsion-bar detector with quantum NOn-demolition Speed meter) is a proposed gravitational-wave telescope designed to operate in the low-frequency band of 0.1–10 Hz. Using cryogenic torsion bars and a Sagnac speed-meter interferometer, CHRONOS aims to achieve a strain sensitivity of approximately 10⁻¹⁸ Hz⁻¹/² near 2 Hz. Its high sensitivity also opens up the possibility of directly measuring gravity-gradient signals for geophysical applications.

In this talk, I will discuss the prospects for gravity-gradient observations with CHRONOS, focusing on Newtonian noise induced by seismic Rayleigh waves and transient gravitational signals generated by earthquakes. I will present our theoretical predictions for these signals and explore their potential applications to earthquake monitoring and early warning.