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Abstract Landslides pose a significant hazard worldwide. Despite advances in landslide monitoring, predicting their size, timing, and location remains a major challenge. We revisit the 2017 Mud Creek landslide in California using radar interferometry, pixel tracking, and elevation change measurements from satellite and airborne radar, lidar, and optical data. Our analysis shows that pixel tracking of optical imagery captured the transition from slow motion to runaway acceleration starting ~ 1 month before catastrophic failure—an acceleration undetected by satellite InSAR alone. Strain rate maps revealed a new slip surface formed within the landslide body during acceleration, likely a key weakening mechanism. Failure forecast analysis indicates the acceleration followed a hyperbolic trend, suggesting failure time could have been predicted at least 6 days in advance. We also inverted for the landslide thickness during the slow-moving phase and found variations from < 1 to 36 m. While thickness inversions provide important first-order information on landslide size, more work is needed to better understand how landslide subsurface properties and deforming volumes may evolve during the transition from slow-to-fast motion. Our findings underscore the need for integrated remote sensing techniques to improve landslide monitoring and forecasting. Future advancements in operational monitoring systems and big data analysis will be critical for tracking slope instability and improving regional-scale failure predictions. 

Abstract In their article entitled “Trapdoor Fault Activation:A Step Toward Caldera Collapse at Sierra Negra,Galapagos,Ecuador” Shreve and Delgado (2023,https://doi.org/10.1029/2023jb026437) examine co‐eruptive deformation during the 2018 eruption of Sierra Negra Volcano. One of their major conclusions is that the 2018 eruption, and specifically co‐eruptive faulting, represents the initial stages of caldera collapse. They reach this conclusion because they focus their analysis solely on co‐eruptive deformation, and do not investigate the total (net) deformation for the 2005 to 2018 eruption cycle. Bell, La Famina, et al. (2021,https://doi.org/10.1038/s41467‐021‐21596‐4) investigated both the pre‐ and co‐eruptive phases of the 2018 eruption and showed that net deformation was one of caldera resurgence, not subsidence. In this comment, we demonstrate that the conclusion of collapse, or even initiation of collapse, is attributable to not accounting for pre‐eruptive deformation on the intra‐caldera Trapdoor Fault system and incorrectly assuming that the volcano‐tectonic dynamics of Sierra Negra mimic those of other basaltic calderas.