The value of terrain pattern, high-resolution data and ensemble modeling
for landslide susceptibility prediction
Abstract
Landslide risk is traditionally predicted by process-based models with
detailed assessments or point-scale, attribute-based machine learning
(ML) models with first- or second-order features, e.g., slope, as
inputs. One could hypothesize that terrain patterns might contain useful
information that could be extracted, via computer vision ML models, to
elevate prediction performance beyond that achievable with low-order
features. We put this hypothesis to the test in the state of Oregon,
where a large landslide dataset is available. The image-processing
convolutional neural networks (CNN2D) using 2D terrain data obtained
either higher Precision or higher Recall than attribute-based random
forest (RF1D) models, but could not improve both simultaneously. While
CNN2D can be set up to identify more real events, it would then
introduce more false positives, highlighting the challenge of
generalizing landslide-prone terrain patterns and the potential omission
of critical factors. However, ensembling CNN2D and RF1D produced overall
better Precision and Recall, and this cross-model-type ensemble was
better than other ways to ensemble, leveraging information content of
fine-scale topography while suppressing its noise. These models further
showed robust results in cross-regional validation. Our perturbation
tests showed that 10m resolution (the smallest possible) produced the
best model in a range of resolutions. Rainfall, land cover, soil
moisture, and elevation were the most important predictors. Based on the
results of the analysis, we generated landslide susceptibility maps,
providing insights into spatial patterns of landslide risk.