EGU23-5686
https://doi.org/10.5194/egusphere-egu23-5686
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

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

Léo Marconato1, Marie-Pierre Doin1, Laurence Audin1, Nicolas Harrichhausen1, Jean-Mathieu Nocquet2,3, Paul Jarrin3,4, and Frédérique Rolandone4
Léo Marconato et al.
  • 1Univ. Grenoble Alpes,  Univ. Savoie Mont Blanc, CNRS, IRD, Univ. Gustave Eiffel, ISTerre, 38000 Grenoble, France
  • 2Université Paris Cité, Institut de Physique du Globe de Paris, Paris, France
  • 3Université Côte d’Azur, IRD, CNRS, Observatoire de la Côte d’Azur, Géoazur, 06560 Valbonne, France
  • 4Sorbonne Université, Institut des Sciences de la Terre Paris, ISTeP, UMR 7193, F-75005 Paris, France

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.

How to cite: Marconato, L., Doin, M.-P., Audin, L., Harrichhausen, N., Nocquet, J.-M., Jarrin, P., and Rolandone, F.: Can we observe North Andean Sliver motion using long InSAR time-series analysis?, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5686, https://doi.org/10.5194/egusphere-egu23-5686, 2023.