The Galapagos hotspot has a very complicated tectonic setting. It is located very close to the spreading ridge between the Cocos and Nazca plates; the hotspot interacts with both plates and the spreading ridge over the last twenty million years as the relative location of the hotspot in relation to the plates has varied. Based on similar seismic velocity gradients of the lavas of the Carnegie, Cocos and Malpelos Ridges there is evidence that the hotspot activity has been the result of a single long mantle melt rather than multiple periods of activity and dormancy.[3]