Landslide monitoring and early warning: theories and technologies

Forecasting landslide failure time is challenging but critical for reducing the casualties and economic losses caused by slope failures. Although substantial progress has been made in landslide-monitoring and early-warning theories and technologies, a systematic review remains lacking. This study summarizes recent advances in landslide-monitoring technologies, early-warning methods and systems, and their typical applications. At present, the traditional single-monitoring mode has evolved into an integrated Space-Air-Ground-In-Situ multi-dimensional cooperative monitoring system, and landslide observation is shifting from single-point measurement to a Cloud–Edge–End collaborative sensing paradigm. Representative early-warning methods include the inverse velocity, Newton force, and improved tangent angle methods. Landslide warnings have also gradually evolved from empirical judgment and single-threshold identification to quantitative warnings supported by continuous monitoring data and multi-indicator coupling analysis. Finally, the limitations of current landslide-monitoring and early-warning systems are discussed, and recommendations for future research are presented.