**5. Conclusions**

This study is an effort to establish thresholds in intensity-duration plane based on antecedent rainfall data for the Idukki district in Kerala State at a regional scale. This is the first of its kind for the region and can be improved on with the availability of short term rainfall data.

The analysis was conducted using a database of 9 years from 2010 to 2018, which included 225 landslide events occurring at different parts of the district, and the principal observations can be summarized as:


**Author Contributions:** Data curation, M.T.A. and D.P.; Formal analysis, M.T.A. and D.P.; Supervision, N.S.; Writing—original draft, M.T.A.; Writing—review & editing, N.S.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors are grateful to Geological Survey of India Kerala State Unit, Kerala State Disaster Management Authority (KSDMA) and District Soil Conservation Office, Idukki for the support they have offered for the research. The authors are also grateful to all the three reviewers for their constructive suggestions.

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