Speaker
Description
Subsurface density monitoring is essential for geohazard mitigation, yet it remains challenging, for instance in deep-seated landslides and around metropolitan infrastructures where conventional methods are not often neither cost effective nor practical for continuous observation. We present MULE (MUon Lightweight Explorer), a portable plastic-scintillator-based muon detection system suitable for continuous monitoring of subsurface density anomalies such as cavities, saturated zones, and structural variations. The system has been tested in multiple field experiments: along the Tokyo Metropolitan subway, and at a large rainfall-induced landslide site in volcanic tuff formations. Preliminary results show a correlation between muon flux and overburden thickness, and possibly sensitivity to saturation level variations associated with environmental changes. These results highlight MULE's potential for continuous real-time density monitoring across a range of applications, from geohazard early warning systems to tunnel excavation and operation, and potentially CO₂ plume monitoring, and mineral exploration.