What type of geophysical testing involves the use of vibrations to determine aquifer materials?

Seismic refraction is a geophysical testing method that employs vibrations to determine the properties and materials of aquifers. This technique works by sending seismic waves into the ground. When these waves encounter different types of materials, such as varying densities of soil or rock layers, they will refract or change direction. By analyzing the travel times of these waves and how they are refracted at different interfaces, geologists can infer the depth and types of materials present in the subsurface.

The effectiveness of seismic refraction lies in its ability to provide detailed information about the subsurface layers, which is crucial for groundwater studies. Seismic refraction can help in identifying the boundaries between different aquifer materials, distinguishing between water-saturated and unsaturated zones, and estimating the depth to bedrock or other geological formations.

Other methods like ground penetrating radar and electrical resistivity, while useful for subsurface investigations, do not utilize vibrations in the same way. Ground penetrating radar primarily relies on electromagnetic pulses to create images of the subsurface, while electrical resistivity measures the resistance of the ground to electrical currents for assessing subsurface materials. Aerial resistivity involves similar principles but is done from the air, making direct comparisons to seismic methods inappropriate.