Can we observe North Andean Sliver motion using long InSAR time-series analysis? - Archive ouverte HAL Accéder directement au contenu
Poster De Conférence Année : 2023

Can we observe North Andean Sliver motion using long InSAR time-series analysis?

Résumé

In Northern Andes, oblique subduction of the Nazca plate below the South America Plate induces a northward motion of the North Andean Sliver, at a rate of ~10 mm/yr with respect to Stable South America. In Ecuador in particular, the associated strain is mainly accomodated along the large Chingual-Cosanga-Puna-Pallatanga (CCPP) fault system, which hosted several 7+ magnitude earthquakes in the historical period. Recent studies using block-modeling of GNSS data raise important questions about the partitioning and the localization of the deformation both inside and at the limits of the North-Andean sliver. Therefore, time-series analysis of InSAR data, allowing a large spatial resolution, would complement the existing geodetic dataset of observation of low-rate crustal motions in this region. Taking advantage of 7 to 8 years of Sentinel-1 archive, we compute long time-series of InSAR data for the whole Interandean region of Ecuador (~100 by 400 km), using the NSBAS processing chain. Because processing of InSAR data in this ecuatorial region raises several challenges, such as low-coherence due to vegetation, ionospheric and troposheric noise, and fading signals,we develop strategies to mitigate the noise terms. By using an optimized interferogram network, improvedweighting during multilooking, and a temporal decomposition of the time-series, we produce the first InSAR velocity maps of the Ecuadorian Cordilleras. We then compare these results to the existing block-model derived from GNSS horizontal data in order to evaluate the possibility of characterizing the motion of North Andean Sliver with an increased spatial resolution.
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Dates et versions

hal-04190675 , version 1 (29-08-2023)

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Léo Marconato, Marie-Pierre Doin, Laurence Audin, Nicolas Harrichhausen, Jean-Mathieu Nocquet, et al.. Can we observe North Andean Sliver motion using long InSAR time-series analysis?. EGU General Assembly 2023, Apr 2023, Vienna, Austria. , 2023, ⟨10.5194/egusphere-egu23-5686⟩. ⟨hal-04190675⟩
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