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Deformation of the Ecuadorian Inter-Andean valley and surroundings from a combined InSAR-GNSS velocity field 2017–2023.

Abstract:

We present a survey of deformation in the Ecuadorian Inter-Andean valley and surrounding regions from satellite radar and GNSS between 2017 and 2023, including anthropogenic, tectonic, landsliding and volcanic processes. Major anthropogenic signals include urban subsidence associated with water and resource extraction in Quito (−3.5 mm/yr), Cañar (+1.8 mm/yr) and Guayaquil (+∼8 mm/yr). We also observe significant horizontal deformation caused by the interaction between the subduction zone and active tectonic faults. Four of Ecuador's 21 continental volcanoes are actively deforming and we also observed the continued subsidence of old volcano-sedimentary deposits in the northeast of the city of Cuenca. We examine the portion of the Chingual-Cosanga-Pallatanga-Puna right-lateral fault (CCPP) between the cities of Pallatanga and Riobamba and determine the geodetic slip rate and strain rate of this particular segment of the fault system and subsequently compare it with previously estimated geological slip rates. We estimated a slip rate of 3.1 ± 0.6 mm/yr, with shear strain ranging from 50 to 100 nst/yr, extending beyond the primary fault trace. Furthermore, shear strain extends southeastward (within a range of 16–30 km), where significant active branches of this complex fault system exist, with a slip rate of 2.7 ± 0.3 mm/yr. This study highlights specific areas for future monitoring of geohazards and infrastructure resilience in Ecuador, with particular relevance for similar Andean settings.