John "Jack" Ertle Oliver (September 26, 1923 – January 5, 2011) was an American scientist. Oliver, who earned his PhD at Columbia University in 1953, studied earthquakes and ultimately provided seismic evidence supporting plate tectonics. In the 1960s, Oliver and his former graduate student, Bryan Isacks, set up seismographic stations in the South Pacific to record earthquake activity, and the data collected led to the insight that part of the ocean floor was being pushed downward.