A review of recent advances in methods for extracting broadband surface waves from ambient noise data

Ambient noise tomography (ANT) has emerged as a major frontier in seismology over the past two decades due to its high resolution, non-invasive, and non-destructive characteristics. ANT enables imaging of detailed structures of the Earth’s interior at multiple scales, providing essential insights into geodynamic and evolutionary processes, urban underground safety, hydrocarbon and geothermal resource exploration, and seismic hazard assessment. Early studies primarily focused on the extraction of fundamental-mode Rayleigh and Love waves in ~5–40 s period band, which provided key constraints on crustal velocity structures and anisotropy. With the deployment of dense seismic arrays and advances in data processing, it is now possible to extract both fundamental and higher-mode surface waves across a much broader frequency range, from a few hertz to several hundred seconds. This review synthesizes recent methodological advances in extracting broadband surface waves from ambient noise data, highlights current challenges and potential solutions in ANT, and outlines future research directions. The goal is to further advance ANT and expand its applications to probing Earth’s internal structure as well as planetary exploration on Mars and other extraterrestrial bodies.