Abstract. Event-based landslide inventories are important for
analyzing the relationship between the intensity of the trigger (e.g.,
rainfall, earthquake) and the density of the landslides in a particular
area as a basis for the estimation of the landslide probability and the
conversion of susceptibility maps into hazard maps required for risk
assessment. They are also crucial for the establishment of local rainfall
thresholds that are the basis of early warning systems and for evaluating
which land use and land cover changes are related to landslide occurrence. The
completeness and accuracy of event-based landslide inventories are crucial
aspects to derive reliable results or the above types of analyses. In
this study, we generated a relatively complete landslide inventory for the
2018 monsoon landslide event in the state of Kerala, India, based on two
inventories that were generated using different methods: one based on an object-based image analysis (OBIA) and the other on field surveys of damaging
landslides. We used a collaborative mapping approach based on the visual
interpretation of pre- and post-event high-resolution satellite images (HRSIs)
available from Google Earth, adjusted the two inventories, and digitized
landslides that were missed in the two inventories. The reconstructed
landslide inventory database contains 4728 landslides consisting of 2477
landslides mapped by the OBIA method, 973 landslides mapped by field survey, 422
landslides mapped both by OBIA and field methods, and an additional 856
landslides mapped using the visual image (Google Earth) interpretation. The
dataset is available at https://doi.org/10.17026/dans-x6c-y7x2 (van Westen, 2020). Also, the location of the landslides was adjusted,
based on the image interpretation, and the initiation points were used to
evaluate the land use and land cover changes as a causal factor for the 2018
monsoon landslides. A total of 45 % of the landslides that damaged
buildings occurred due to cut-slope failures, while 34 % of those having an impact on roads were due to road cut-slope failures. The resulting landslide
inventory is made available for further studies.