文章基本信息

标题：Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia, revealed by advanced InSAR
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作者：Roberts, Nicholas J. ; Rabus, Bernhard T. ; Clague, John J. 等
期刊名称：Natural Hazards and Earth System Sciences
电子版ISSN：2195-9269
出版年度：2019
卷号：19
期号：3
页码：679-696
DOI：10.5194/nhess-19-679-2019
语种：English
出版社：Copernicus Publications
摘要：We characterize and compare creep preceding and followingthe complex 2011 Pampahasi landslide (∼40Mm3±50%) in the city of La Paz, Bolivia, using spaceborne radarinterferometry (InSAR) that combines displacement records from bothdistributed and point scatterers. The failure remobilized deposits of anancient complex landslide in weakly cemented, predominantly fine-grainedsediments and affected ∼1.5km2 of suburban development.During the 30 months preceding failure, about half of the toe area wascreeping at 3–8cma−1and localized parts of the scarp area showeddisplacements of up to 14cma−1. Changes in deformation in the 10 monthsfollowing the landslide demonstrate an increase in slope activity andindicate that stress redistribution resulting from the discrete failuredecreased stability of parts of the slope. During that period, most of thelandslide toe and areas near the head scarp accelerated, respectively, to4–14 and 14cma−1. The extent of deformation increased to cover most, orprobably all, of the 2011 landslide as well as adjacent parts of the slopeand plateau above. The InSAR-measured displacement patterns, supplemented byfield observations and optical satellite images, reveal complex slopeactivity; kinematically complex, steady-state creep along pre-existingsliding surfaces accelerated in response to heavy rainfall, after whichslightly faster and expanded steady creeping was re-established. This casestudy demonstrates that high-quality ground-surface motion fields derivedusing spaceborne InSAR can help to characterize creep mechanisms, quantifyspatial and temporal patterns of slope activity, and identify isolatedsmall-scale instabilities; such details are especially useful whereknowledge of landslide extent and activity is limited. Characterizing slopeactivity before, during, and after the 2011 Pampahasi landslide isparticularly important for understanding landslide hazard in La Paz, half ofwhich is underlain by similar large paleolandslides.