This is incredible. If you look closely in satellite imagery you can still see the effect of the pressure wave moving through the atmosphere, even as far as the west coast of the US, more than 8000km away. To help make it more visible,
I used "grain extract" layer blending in GIMP to emphasize pixels that change between frames. (The white crescent sweeping from right to left is Earth's terminator.)
I calculated that the wave speed is slightly slower than the speed of sound at sea level. About 300 m/s instead of 340 m/s. This might make sense if we think of the speed of sound averaged through the lower atmosphere. As you go up in altitude, the temperature is colder, and the sound speed is slower.
As I watched the wave approach by satellite imagery I wondered if I could notice it as it passed by. I didn't think I would be able to. I went out about 10 minutes before it was due to arrive, and there were patches of fog over the water and a mid-level layer of broken clouds. Sure enough, as the wave passed, the fog slowly evaporated for a few minutes, and then reformed. The mid-level clouds also shifted.
It was all so subtle that you'd never notice or think twice about it if you did not know to look for it. But it definitely happened. It was exactly like how clouds behave in footage of nuclear explosions when the shockwave passes through them, just slower. It was extremely weird.
I'm still kind of stunned by it. I never expected to see such a thing in my life, especially from an eruption so far away.
There was no sound at all, of course. The "wavelength" is far too long.