Scientists have used seismic waves to identify chemical reactions that occur below the surface of Earth. These reactions have the potential to change the quality of groundwater.
The study was carried out by a team of researchers led by Penn State University. They believe that 'seeing' under an entire watershed may help protect the groundwater resources.
During the research, published in the journal Proceedings of the National Academy of Sciences, the team relied on human-generated seismic waves, similar to what generated from an earthquake.
The researchers dipped instruments in a 115-foot deep borehole. It is located at the Susquehanna Shale Hills Critical Zone Observatory, which is a forested research site.
The logging tool helped produce and propagate a seismic wave, which is used to examine the structure of the interior of the earth. The examination is carried out by monitoring the behaviour of waves – how they propagate, reflect, and refract.
By sending a seismic wave, its velocity was calculated to observe the nature of the surface through which it passed.
High velocity pointed out that the wave was travelling "solid bedrock or where pores in weathered rock are filled with water " whereas slow velocity hinted that it was moving through "weathered rock with air-filled pores or soil near the surface."
The team by monitoring the behaviour of the wave got to know where the water had reacted with clay, causing small changes.
They authenticated their finds by comparing it with data obtained from borehole drilling in 2006 and 2013.