Geophysicists collect seismic data in the same way as earthquake seismologists. Elastic waves propagate through the Earth as a result of earthquakes. The ground motions caused by elastic wave propagation are then recorded by seismologists using a seismograph. A controlled seismic source of energy, but one that is much lower than an earthquake, is used in seismic exploration to generate elastic waves that propagate through the subsurface. Multiple receivers at the surface detect and record reflected seismic energy. © 2022 Elsevier Inc. All rights reserved.