Geologists apply various methods to study the layers of the Earth. Which of the following is NOT a method used to study the Earth’s layers? A. Scientists use seismic computer models to measure the atmospheric conditions above the Earth's crust

B. Scientists map seismic waves to determine the densities of materials that lie beneath Earth’s surface.

C. Scientists measure vibrations on Earth's surface using a seismograph (an instrument that measures seismic waves).

D. Scientists measure the time it takes for seismic waves to reach a seismograph (an instrument that measures seismic waves).