Last Saturday

Does anybody know what caused that loud noise last Saturday night?

It came in two waves each lasting a good half minute. Our first thought was an earthquake but then there was no corresponding movement. Then we thought of thunder but it wasn't like that. We went onto the roof to look but couldn't see anything.

I've checked online for earthquakes in this area and there have been none just recently. There was a quake on Saturday but it was only 1.6 on the Richter scale and its epicentre was miles away. I doubt if we would have heard it here.

I've looked in the local papers and can find no reference to anything that might have caused the noise.

So it remains a mystery until someone comes up with an explanation.