It sounds like metal scraping. Big machines boring underground tunnels. My father works for an underground boring company and he said that that is very familiar sounding. Explosions are due to bombs to blow through sedimentary rocks and such??? – Commenter

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https://www.youtube.com/watch?v=SQGtYxRuWd8

What Are the Strange Sounds Being Heard Around the World?

Published on Nov 24, 2017

Have you heard the strange sounds and loud booms that have been reported around the world? What is your take on this strange phenonmenon?