I read up on that when this was originally reported. I think it was during the early days of Pizzagate. Some thought the second coming was about to happen. They definitely have tectonic activity in that part of the world. I wasn't far from Alexandria, Egypt when it was leveled in an earthquake in '95.
I have read somewhere that deep earth tectonic activity can cause this "trumpet" sound. It has been reported elsewhere during or before earthquakes.
https://www.sandiegouniontribune.com/opinion/the-conversation/sdut-mysterious-noises-sky-worldwide-2015may19-htmlstory.html
Google "earthquake trumpet sound" for video examples.
I read up on that when this was originally reported. I think it was during the early days of Pizzagate. Some thought the second coming was about to happen. They definitely have tectonic activity in that part of the world. I wasn't far from Alexandria, Egypt when it was leveled in an earthquake in '95.