"By mapping fiber optic cables accurately, we can transform them into dense seismic arrays. This opens the door to city-scale imaging and monitoring." Haipeng Li explains how distributed acoustic sensing (DAS) can turn existing urban fiber optic cables into powerful seismic arrays for near-surface imaging and monitoring. By using everyday traffic and ambient noise, his team can track groundwater changes, detect geohazards, and study fault structures without costly field deployments. This approach offers a new way for geophysicists, engineers, and city planners to work together for safer, more resilient urban environments. KEY TAKEAWAYS > Existing fiber optic cables can be transformed into dense, city-scale seismic arrays using DAS technology. > Vehicle-induced seismic waves provide highly repeatable data for monitoring small subsurface changes, while ambient noise helps extend imaging depth. > Urban DAS monitoring can reveal how infrastructure affects groundwater recharge and can support hazard assessment and infrastructure planning. GUEST BIO Haipeng Li is a third-year Ph.D. candidate in the Geophysics Department at Stanford University, advised by Biondo Biondi in the Stanford Earth Imaging Project (SEP). His research centers on spatiotemporal subsurface monitoring, with a focus on developing efficient and robust time-lapse seismic waveform inversion methods and uncertainty quantification approaches. He applies these techniques to real-world challenges such as geological CO2 sequestration for the energy transition and groundwater monitoring in urban environments, often leveraging Distributed Acoustic Sensing (DAS) data. He is a student member of the AGU, SSA, and SEG. LINKS * Haipeng Li, Jingxiao Liu, and Biondo L. Biondi, (2025), "Near-surface imaging and monitoring enabled by urban distributed acoustic sensing seismic arrays," The Leading Edge 44: 588–597. - https://doi.org/10.1190/tle44080588.1