Annual to millennial landslide inventories and hillslope erosion in NW Argentine Andes
Final Report Abstract
The Quebrada del Toro in the Eastern Andes is a natural laboratory where high magnitude and dynamic erosion processes can be regularly observed. The seasonal climate and monsoon activity provides a driving force for mass movements in this area. This projected supported research from space and on-the-ground field work. First, data from radar and optical satellites were used to better understand the spatial distribution of landslides and debris flows in the steep gorge at the eastern flanks of the Central Andean Plateau. The radar-based coherence assessment documents the seasonal activity of debris flows and that these data can be used to understand transport in the hillslope and fluvial regime. We identify the time series of radar coherence data as a proxy for landscape denudation rates: a robust correlation with cosmogenic radionuclide-based denudation rates is shown. This provides an alternative to estimate millennial-timescale erosion rates and landscape steepness assessments. High-resolution optical data from different viewing angles allow to create 3-m digital elevation models that can be used to better describe channels and their debris flow activity. A debris-flow similarity index was developed that documents the impact of structural preconditioning and geologic history on massmovement generation. Both (optical and radar) satellite-based assessment provide opportunities to measure mass-transport rates and perform a natural hazard assessment. The intersection of satellite-based data with ground validation is an important component of successful satellite-based assessments. An important component of quantifying and understanding processes at the earth surface are digital elevation models. This projected supported several field campaigns that collected detailed topographic validation data that was used in several peer-reviewed studies. New approaches to develop high-resolution topography from stereo-satellite images were explored. In a second step, this project investigated cm-scale observations on the ground with specific focus on the description of sediment-transport processes. A new method was developed to measure large quantities of pebbles (i.e., digital grain sieving) through high-resolution stereo-photogrammetry. These data indicate that there are significant changes only in the highest percentile of the grain-size distributions. This tools is an open-source project and is used by other researcher to perform grain-size measurements. Further development of this tool is ongoing and approaches with convolutional neural networks within machine learning frameworks are explored. This project was a close international collaboration with colleagues at academic institutions in northwestern Argentina. Joint field studies and personal exchanges were carried out that fostered knowledge transfer and education on both sides.
Publications
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Mapping Damage-Affected Areas after Natural Hazard Events Using Sentinel-1 Coherence Time Series. Remote Sensing, 10(8), 1272.
Olen, Stephanie & Bookhagen, Bodo
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Introducing PebbleCounts : a grain-sizing tool for photo surveys of dynamic gravel-bed rivers. Earth Surface Dynamics, 7(3), 859-877.
Purinton, Benjamin & Bookhagen, Bodo
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Applications of SAR Interferometric Coherence Time Series: Spatiotemporal Dynamics of Geomorphic Transitions in the South‐Central Andes. Journal of Geophysical Research: Earth Surface, 125(3).
Olen, Stephanie & Bookhagen, Bodo
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Multiband (X, C, L) radar amplitude analysis for a mixed sand- and gravel-bed river in the eastern Central Andes. Remote Sensing of Environment, 246, 111799.
Purinton, Benjamin & Bookhagen, Bodo
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Beyond Vertical Point Accuracy: Assessing Inter-pixel Consistency in 30 m Global DEMs for the Arid Central Andes. Frontiers in Earth Science, 9.
Purinton, Benjamin & Bookhagen, Bodo
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Identification of Debris‐Flow Channels Using High‐Resolution Topographic Data: A Case Study in the Quebrada del Toro, NW Argentina. Journal of Geophysical Research: Earth Surface, 126(12).
Mueting, A.; Bookhagen, B. & Strecker, M. R.
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Tracking Downstream Variability in Large Grain‐Size Distributions in the South‐Central Andes. Journal of Geophysical Research: Earth Surface, 126(8).
Purinton, Benjamin & Bookhagen, Bodo
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Image Texture as Quality Indicator for Optical DEM Generation: Geomorphic Applications in the Arid Central Andes. Remote Sensing, 15(1), 85.
Purinton, Benjamin; Mueting, Ariane & Bookhagen, Bodo
