I live in the mountains of Western North Carolina, USA. Over the past several months I have noticed a vibration that feels to me as though coming through the earth and shaking the house. These come in episodes and feel to be just subsonic not unlike a heavy truck rolling by on the highway - the problem being that there’s no highway that close to where I live now. The episodes last 10 - 30 seconds, may repeat, might not. This is a daily occurrence. I wish to use my Raspberry Shake to identify the pattern and try to find out where it’s coming from. I will keep the forum posted.
Excellent. Thank you for keeping us informed about your special use case. We would love to hear more as time goes on.