GPR survey on underwater archaeological site: A case study at Jenipapo stilt village in the eastern Amazon region, Brazil

•This work shows a pioneering GPR application for underwater archaeology investigation in the eastern Amazon region in Brazil.•GPR results permit to map with high-resolution the Turiaçu River bottom and detect the top of the wooden pillars that supported the pre-colonial stilt villages.•The wooden pillars were characterized as diffraction hyperbolas suspended over the Turiaçu River bottom.•GPR numerical modeling presented a good agreement with real data which aided the results interpretation.•GPR results can guide the search for artifacts between the wooden pillars in the underwater archaeological site.•The results can contribute to reduce the costs of the archaeological investigation and help to improve the knowledge about the underwater archaeological site in the eastern Amazon region, Brazil.