Which technological tool helps earth scientists gain new knowledge about earth’s subsurface?hydrometerground penetrating radarglobal positioning systemdigital balance

The technological tool that helps earth scientists gain new knowledge about earth’s subsurface is the Ground Penetrating Radar (GPR).

Here's a step-by-step explanation:

1. Ground Penetrating Radar is a geophysical method that uses radar pulses to image the subsurface.

2. This nondestructive method uses electromagnetic radiation in the microwave band (UHF/VHF frequencies) of the radio spectrum, and detects the reflected signals from subsurface structures.

3. GPR can be used in a variety of media, including rock, soil, ice, fresh water, pavements and structures.

4. It can detect objects, changes in material, and voids and cracks.

5. GPR uses high-frequency (usually polarized) radio waves, usually in the range 10 MHz to 2.6 GHz.

6. A GPR transmitter emits electromagnetic energy into the ground. When the energy encounters a buried object or a boundary between materials having different permittivities, it may be reflected or refracted or scattered back to the surface.

7. A receiving antenna can then record the variations in the return signal.

8. The principles involved are similar to seismology, except GPR methods implement electromagnetic energy rather than acoustic energy, and energy may be reflected at boundaries where subsurface electrical properties change.

So, by using GPR, earth scientists can gain new knowledge about the earth's subsurface.