With regard to my previous post, another observation was that yesterday morning my dog didn’t eat his breakfast. He spent most of the day cowering. We thought he had injured himself somehow but there were no visible signs. I checked his joints and pressed his gums to watch the circulation return and everything was normal. We agreed to keep him indoors today. A few minutes ago it occured to me that he may have been sensing the 6.0 magnitude aftershocks that they were experiencing in SW China all day yesterday. Today he’s fine – and he enjoyed his breakfast very much. 😉
I also have an improved theory on why the house we’re staying in in Elizabeth, Colorado is sensitized to these vibrations…
The basement is underground and the floor above the basement is at ground level. The entire basement is closed up i.e. all doors are closed and there’s a single exit via some stairs to get up to ground level.
So the basement acts as a giant resonance chamber much like the boxes they use to mount sub-woofers. The chamber is tuned to very low frequencies because of its size. As a wave form enters it starts bouncing within the chamber with very little loss. As additional waves enter the chamber they reinforce the first wave and eventually you have a standing wave that is of a great enough amplitude to set the floor above the basement vibrating.
Viola! Instant long-range seismometer.
So this household (forgive the pun) seismometer detects what’s known as teleseismic events. These are Earthquakes that are detected more than 1000km’s from the source. And there is in fact an amateur teleseismic network that has a ton of info about Earthquakes in general and these sorts of Earthquakes. Here’s a quote:
The dynamic, transient seismic waves from any substantial earthquake will propagate all around and entirely through the Earth. Given a sensitive enough detector, it is possible to record the seismic waves from even minor events occurring anywhere in the world an any other location on the globe. Nuclear test-ban treaties in effect today rely on our ability to detect a nuclear explosion anywhere equivalent to an earthquake as small as Richter Magnitude 3.5.
Rest of the source article is here.