CHRONOS: A Cryogenic Sub-Hz Gravitational-Wave Detector That Could Also Serve as an Earthquake Early-Warning System
CHRONOS is a proposed ground-based gravitational-wave detector targeting the 0.1–10 Hz band — a regime currently inaccessible to instruments like LIGO due to dominant noise floors. It combines cryogenic cooling, a cross torsion-bar mechanical isolation scheme, a triangular Sagnac interferometer, and a quantum non-demolition speed meter readout to suppress thermal, quantum, and environmental noise. Noise budget simulations using FINESSE3 confirm competitive strain sensitivity of ~10⁻¹⁸ Hz⁻¹/² at 2 Hz. A dual-use application for earthquake early warning via prompt gravity-gradient detection is also predicted, with a 2.92–6.90 second lead time advantage over seismic wave arrival within 40 km.