Hello Mountains703, welcome to the community!
Thank you for all the information you have provided. I cross-checked your day and time of the event with the USGS earthquake database, and there is nothing close to what you detected in your area, so I think that that big spike has been caused by some kind of artificial disturbance in your vicinity.
But if anyone else in the forum has a better idea, feel free to add your thoughts!
Could that be related to the Spike Mystery…The Spike Mystery
I noticed a similar spike on mine for a different event (Vancouver, Canada) on April 5, 2021 @ 23:39 UTC. At first, I thought it was a quake but nothing showed up on USGS. I confirmed with another Shake nearby, and sure enough, the event registered on that unit as well. Then, about 2 days later, it actually did show up on the USGS. Moral of the story: did the event show up on other nearby Shakes? Perhaps the USGS is delayed. That being said, I just cross-checked but did not see anything on the USGS database for that day or time so perhaps it is an isolated local event.
I would also try to zoom in a bit more, the X axis is quite broad for an event that lasts a few seconds. In your first image, the view is 10 minutes and makes the pattern difficult to interpret. From what I can tell, I don’t see the exponential decay that I would normally expect, or the sudden ‘snap’ at the beginning. But again, hard to tell from the scale.
On another note, that’s a very quiet, noise free signal! Your shake must me in a very remote area?
How do I get my Shake to record data on the Community Events log?
Deanna L. Mitchell