Acoustic patterns reveal unstable regions of the Earth’s crust

2023-10-11 12:53:53

MADRID, 11 Oct. (EUROPA PRESS) –

Geologists from MIT (Massachusetts Institute of Technology) have discovered that the sounds recorded underground are fingerprints of rock stability.

The fissures, pores and defects that run through rocks are like strings that resonate when pressed and strained, and the rhythm of these sounds can say something about the depth and strength of the rocks. “If you were listening to the rocks, they would sing in higher and higher pitches as you go deeper,” says MIT geologist Matej Pec.

Peč and his colleagues listen to rocks to see if acoustic patterns emerge or “fingerprints” when subjected to different pressures. In laboratory studies, they have now shown that marble samples, when subjected to low pressures, emit low-pitched “cracks”, while at higher pressures, the rocks generate an “avalanche” of higher-pitched crackles.

Peč says these acoustic patterns in rocks can help scientists estimate the types of cracks, fissures and other defects the Earth’s crust experiences with depth, which they can then use to identify unstable regions beneath the surface. where there is potential for earthquakes or eruptions.

The team’s results, published in the Proceedings of the National Academy of Sciences, could also help inform surveyors’ efforts to drill in search of renewable geothermal energy.

“If we want to tap into these very hot geothermal sources, we’re going to have to learn how to drill into rocks that are in this mixed state, where they’re not purely brittle, but also flow a little bit,” he says. it’s a statement Pec, who is an assistant professor in the Department of Earth, Atmospheric and Planetary Sciences (EAPS) at MIT. “But overall, this is fundamental science that can help us understand where the lithosphere is strongest.”