Abstract. Landslides in glacial environments are high-magnitude,
long-runout events, believed to be increasing in frequency as a paraglacial
response to ice retreat and thinning and, arguably, due to warming
temperatures and degrading permafrost above current glaciers. However, our
ability to test these assumptions by quantifying the temporal sequencing of
debris inputs over large spatial and temporal extents is limited in areas
with glacier ice. Discrete landslide debris inputs, particularly in
accumulation areas, are rapidly “lost”, being reworked by motion and
icefalls and/or covered by snowfall. Although large landslides can be
detected and located using their seismic signature, smaller (M≤5.0)
landslides frequently go undetected because their seismic signature is less
than the noise floor, particularly supraglacially deposited landslides, which
feature a “quiet” runout over snow. Here, we present GERALDINE (Google Earth Engine supRaglAciaL Debris INput dEtector): a new free-to-use tool
leveraging Landsat 4–8 satellite imagery and Google Earth Engine. GERALDINE
outputs maps of new supraglacial debris additions within user-defined areas
and time ranges, providing a user with a reference map, from which large
debris inputs such as supraglacial landslides (>0.05 km2)
can be rapidly identified. We validate the effectiveness of GERALDINE
outputs using published supraglacial rock avalanche inventories, and then
demonstrate its potential by identifying two previously unknown, large
(>2 km2) landslide-derived supraglacial debris inputs onto
glaciers in the Hayes Range, Alaska, one of which was not detected
seismically. GERALDINE is a first step towards a complete global
magnitude–frequency of landslide inputs onto glaciers over the 38 years of
Landsat Thematic Mapper imagery.