Risk prediction of catastrophic debris flows against the background of material changes and human engineering activity in the Wenchuan earthquake disturbance area

Abstract

The changes in landslide material and human engineering activities have often posed important impacts on debris flow risk. In this study, multi-period remote sensing images and unmanned aerial vehicle aerial images are used to monitor the prolonged variation in landslide materials transfer for debris flow initiation. Simultaneously the FLO- 2D model and vulnerable curve were used to detect the risk of debris flow in the later period (after 2023). After 15 years of the Wenchuan earthquake, the hillslope landslide materials delivery for debris flow initiation is limited. Impacted by the changes in solid materials, topography and human engineering activities, the risk of debris flow with a recurrence period of 10, and 20 years has been effectively reduced, but for the 50 and 100 years of recurrence period situation, the impact of human engineering activities and channel topography on debris flow risk is limited. For the 10, 20, 50 and 100 years of recurrence period situation, the buildings are at"extreme"and"high"risk was 0, 21, 38, and 115, respectively. Therefore, the monitoring and early warning is still an important measure to reduce economic losses and casualties in the later period.