Geophysical exploration of urban underground space: Current status, trends, and future directions

Urban underground space is a key element for the sustainable development of modern cities. However, its complexity and the concealment of its targets pose ongoing challenges to high-resolution imaging and accurate attribute assessment. While geophysical methods have become crucial due to their non-invasiveness and high penetration, existing research is fragmented and lacks systematic integration from methodological innovation to urban application scenarios. This paper, based on bibliometric analysis and a systematic literature review, outlines the current research status and development trends in this field, integrating the trade-offs between detection depth and resolution with typical application scenarios to construct a clear framework for method selection and information interpretation. Based on this, three possible development paths are proposed: the construction of multi-technology joint exploration and multi-physics monitoring systems; deep learning imaging and intelligent information interpretation processing technologies; and a dynamic safety control system for underground space in smart cities, forming a technological closed loop from data perception and intelligent interpretation to decision-making and execution. This research provides forward-looking geophysical support for urban disaster assessment, spatial planning, and digital modeling, and lays the methodological foundation for future underground space safety and intelligent management.