Let me set the scene by showing where I am, and what Shake stations are in the area. I am near Portland, Oregon. My Shake is the “SB” in blue, top-middle of the map.
Yesterday, I noticed a small earthquake:
It didn’t show up on the app, probably because it was not very powerful. I looked around for any of the other shakes in the area having seen it. The “1D” at the bottom of the map, West of Corvalis did:
Most of the others are in towns, and the noise levels are just too high, or they just didn’t see it. I did a quick plot to try to roughly locate it:
Based upon past activity levels, I would guess that it is the Eastern (inland) intersection.
Well, that was an interesting exercise, then, today, I noticed this from last night:
Somewhat more powerful. Checked the other shakes in the area, and this time, the only one seeing anything was the “1D” just to the East of me, about 7 km away.
This one actually seems powerful enough that I would have expected other stations in the area to have detected it, even above their ambient noise, and for it to have then made its way into the RS database.