Seismic testing is a geophysical technique used to study the Earth's subsurface by generating and recording seismic waves. It involves the controlled release of energy, typically through the use of explosives or specialized equipment, to create seismic waves that travel through the ground. By analyzing the arrival times and characteristics of these waves as they bounce off geological layers and structures underground, seismic testing helps geologists and engineers map subsurface features, locate natural resources like oil and gas, and assess the potential for seismic hazards like earthquakes.