Transforming Cities with Real-Time Passive Geophysical Monitoring

Geophysics has served as a fundamental science for over 140 years and has driven oil and gas exploration for the past seven decades. Its adaptation to urban monitoring applications, however, was long constrained by high costs, labour-intensive field operations, and complex data processing. Recent technological advances, including low-cost nodal sensors, ambient noise as passive sources, real-time data transmission via Wi-Fi and 5G, and artificial intelligence, are now enabling autonomous, real-time geophysical monitoring in several cities of China. Rather than aiming for fully resolved velocity models, urban geophysics can deliver greater practical value by tracking temporal variations in key geophysical attributes. This shift in detection strategy lowers costs, reduces reliance on human intervention, and supports scalable, continuous monitoring of critical infrastructure such as roads, bridges, dams, construction zones, slopes, and buildings. By embedding geophysics intelligence into cities, geophysics evolves from a project-based, resource-driven discipline into a living, responsive nervous system for the urban environment.