Distributed right-lateral strain at the northern boundary of the Quito-Latacunga microblock influenced by arc-volcanism?

Remote sensing and field data indicate distributed right-lateral faulting at the northern edge of the geodetically defined Quito-Latacunga microblock where recent volcanic inflation and seismicity have also been recorded. Off the west coast of Ecuador and Colombia, oblique subduction of the Nazca Plate beneath the South America plate induces northeastward motion of the Northern Andean Sliver relative to stable South America. Recent geodetic studies show this sliver comprises several independent microblocks, with strain accommodated at each of their boundaries. The Quito-Latacunga microblock, located in the densely populated Interandean valley, shows approximately 3 mm/yr of right-lateral strain at its northern boundary. We use available digital terrain models (DTMs), local DTMs derived from Pleiades satellite stereo-imagery, InSAR, Google Earth imagery, and field surveys to demonstrate deformation at the northern boundary is distributed across several northeast-striking right-lateral faults in Ecuador and Colombia. InSAR shows that a recent 2022 M 5.7 earthquake resulted in line-of-sight displacement of 5 cm to 13 cm along one of the east-northeast striking, right-lateral faults. Offset sediments and glacial features indicate recent earthquakes on two other faults north of and subparallel with this rupture. Displaced glacial landforms along one of these faults show slip rates between 0.8 and 6.1 mm/yr, suggesting geologic slip rates that could be higher than geodetic ones. We suggest that ongoing volcanic activity at the nearby Chile-Cerro Negro volcano, and potentially Galeras volcano to the north may influence earthquakes on these faults, enhancing slip and earthquake rates and localizing deformation.