Satellite-Based Assessment of Rainfall-Triggered Landslide Hazard for Situational Awareness

Determining the time, location, and severity of natural disaster impacts is fundamental to formulating mitigation strategies, appropriate and timely responses, and robust recovery plans. A Landslide Hazard Assessment for Situational Awareness (LHASA) model was developed to indicate potential landslide activity in near real-time. LHASA combines satellite-based precipitation estimates with a landslide susceptibility map derived from information on slope, geology, road networks, fault zones, and forest loss. Precipitation data from the Global Precipitation Measurement (GPM) mission are used to identify rainfall conditions from the past 7 days. When rainfall is considered to be extreme and susceptibility values are moderate to very high, a nowcast is issued to indicate the times and places where landslides are more probable. When LHASA nowcasts were evaluated with a Global Landslide Catalog, the probability of detection (POD) ranged from 8% to 60%, depending on the evaluation period, precipitation product used, and the size of the spatial and temporal window considered around each landslide point. Applications of the LHASA system are also discussed, including how LHASA is used to estimate long-term trends in potential landslide activity at a nearly global scale and how it can be used as a tool to support disaster risk assessment. LHASA is intended to provide situational awareness of landslide hazards in near real-time, providing a flexible, open-source framework that can be adapted to other spatial and temporal scales based on data availability. Plain Language Summary Determining where, when, and how landslide hazards may vary and affect people at the global scale is fundamental to formulating mitigation strategies, appropriate and timely responses, and robust recovery plans. While monitoring systems exist for other hazards, no such system exists for landslides. A near global landslide hazard assessment model for situational awareness (LHASA) has been developed to provide an indication of potential landslide activity at the global scale every 30min. This model uses surface susceptibility and satellite rainfall data to provide moderate to high nowcasts. This research describes the global LHASA currently running in near real-time and discusses the performance and potential applications of this system. LHASA is intended to provide situational awareness of landslide hazards in near real-time. This system can also leverage nearly two decades of satellite precipitation data to better understand long-term trends in potential landslide activity.