A new early warning Criterion for assessing landslide risk

A large number of engineering case studies have shown that the traditional early warning criteria, which evolved on the basis of displacement as a single piece of information, have many limitations in practical engineering. The displacement speed ratio (DSR) cannot determine the development trend of landslides due to the influence of periodic external environmental factors. Moreover, when landslides occur, the early warning system will have a false alarm due to the stepwise giant rise of landslides. To solve this problem, this paper proposes a new landslide warning criterion, the trend speed ratio (TSR), and also fuses TSR and DSR into a dual speed ratio method (DSRM) for judging landslide risk changes. We assess these methods by applying DSRM and DSR to 10 landslide cases, respectively. The results show that when TSR is greater than 2.0, the probability of landslide damage is high and when TSR tends to decrease, the landslide tends to be stable. For landslides that rise sharply in steps but are not damaged, DSR has a high false alarm rate, while DSRM can effectively reduce the false alarm rate. In terms of warning applicability, DSR can be applied in only half of the ten landslide cases studied, while DSRM is significantly more applicable. In addition, compared with the traditional method, the new method can determine the direction of landslide development and assess the risk of step-up landslides, providing new technical support for engineers engaged in landslide warning and control.