**5. Conclusions**

A new landslide catalogue was prepared for Wayanad district, Kerala, India, compiling information from different data sources. The catalogue consists of landslide events that happened from 2010 to 2018 in the district. With the available data, rainfall events associated with each landslide was identified using the data from four rain gauges located at different places in the district.

The catalogue was used to determine intensity–duration thresholds on regional and local scales, which is the first attempt of its kind for the study area. Four different approaches were adopted in the study to develop intensity–duration thresholds by varying the selection of rain gauge, area considered and definition of rainfall parameters. After the analysis, it can be concluded that on a regional scale, selecting the rain gauge based on maximum average intensity (Imax) performs better than choosing the nearest rain gauge. Four separate thresholds for each polygon considered are also proposed in this study.

On a regional scale, with 5% exceedance probability, a rainfall of intensity 1mm h−<sup>1</sup> of a one-day duration is potent enough to trigger landslides in Wayanad district. It is also observed that Mananthavady and Vythiri polygons are more susceptible to landslides than the other two regions. The intensity of rainfall of a one-day duration which can possibly trigger a landslide in the Mananthavady, Vythiri, Ambalavayal and Kuppady polygons are 0.97 mm h<sup>−</sup>1, 0.82 mm h−1, 1.26 mm h−<sup>1</sup> and 0.75 mm h−<sup>1</sup> respectively. The Ambalavayal polygon can be considered as a relatively less vulnerable region with a lower number of landslide events and higher threshold values.

The study emphasizes the importance of the preparation of landslide catalogues and determination of rainfall thresholds for Wayanad region. An effective LEWS is an immediate requirement in the region, and the study has to be further enhanced with state-of-the-art models developed for other parts in the world. The existing model can also be conceptually modified using precise field monitoring techniques as well. Attempts must be made to reduce the false alarms to develop an operational rainfall threshold model to function as a Landslide Early Warning System for the region.

**Author Contributions:** Conceptualization, M.T.A., S.S. and N.S.; methodology, M.T.A. and S.S.; data curation, M.T.A.; writing—original draft preparation, M.T.A. and A.R.; writing—review and editing, S.S., B.P. and N.S.; supervision, N.S. and B.P; funding acquisition, S.S. All authors have read and agreed to the published version of the manuscript.

**Funding:** Florence University, in the framework of the project SAMUELESEGONIRICATEN20.

**Acknowledgments:** The authors express their sincere gratitude to Geological Survey of India, Kerala SU, District Soil Conservation Office Wayanad and Kerala State Disaster Management Authority (KSDMA) for their support throughout the study.

**Conflicts of Interest:** The authors declare no conflict of interest.
