Influence of the Carnegie Ridge on the Development of Seismogenic Sources and Seismicity of Ecuador

Abstract

AbstractThe subducting process of Nazca plate beneath the South American tectonic plate governs the seismicity at the Andes region, making it one of the world’s most active seismic regions. The subduction and collision of the aseismic Carnegie Ridge (CR), and the segmentation and drift of the continental North-Andean Block (NAB) with an intricate system of geological faults, are the main seismogenic sources in Ecuador. The oblique convergence of the CR is causing a ploughing effect and shallow-focus earthquakes on the Ecuador shoreline and deep seismic activity in the Pastaza-Napo region at the Amazon basin. The North Andean Block ejection by the Carnegie Ridge collision develops a complex system of active faults along the Andes and shallow-focus earthquakes along Chingual-Cosanga-Pallatanga-Puná fault system. Geodynamic and seismic activity suggests that subduction of the prolongation of CR beneath Ecuador requires about 400 km from the Colombia-Ecuador-Peru trench and is the most influential factor in the development of Ecuador’s seismicity.KeywordsEcuadorCarnegie ridgeNorth andean blockNazca plateSeismic hazardSubductionSeismicity