This is what a passing thunderstorm looks like in infrasound:

The closer lightning is is quite evident.
Outside, it looks and sounds like this:


This is so cool!

Wish I still lived in a place where thunderstorms were more common, but we cannot have everything.

Great signal!

Here, in the Pacific NorthWest, they are rare. This was quite unusual. We usually see a couple of lightning bolts and that’s it. This time was different:

BTW - we are not that far from you, see? Dundee is just down the road!



You are actually way closer to Dundee than I am! :smiley:

Here is the same, climate-wise. We don’t have lots of thunderstorms, maybe once or twice a year, and the strong ones probably come once in 2-3 years.

@PhilipPeake, very nice.

I have been wanting to sample thunder since I got my Rb several months ago. Unfortunately, or maybe fortunately, we do not see much lightning in SoCal. Earthquakes we got, lightning not so much.

At first I spent a few hours in the evenings when the storms looked promising looking at trying to find a ‘local to the storm boom’ where I could see a thunder waveform. The midwest where most of activity is located is sparse on booms.

I finally decided that the way to do it was to map out a few booms and monitor for a storm to show up. I have not yet been able to catch a boom hearing thunder in real time.

Until I saw your post I was not sure what a thunder event would look like.

Thanks again.


We don’t get that much up here in the PNW either. This was a pretty unusual event.
For what it’s worth, it gets picked up pretty well by the seismometer too:

I only remember one good thunderstorm in SoCal - I was eating dinner in my hotel when it started. I realized how rare it was when everyone (but me) got up from their tables go to the windows to watch :slight_smile:


I was waiting for someone from Florida to come in here and post something :wink:

But here in Virginia we get enough lightning action.

Here is a single lighting strike within 1-2 miles as seen on both RB and RS.

In this particular instance the seismic wave(s) arrived first.

The peak of the sound wave was a bit more than 1E6 or 17 Pa (118 dB SPL).

This is loud indoors but not exceptional.


More distant lightning strikes produce less distinct patterns due to reverberation.
If you use the long time-constant mechanical filter, you will see VLF fluctuations due to what (I assume) are vertical air currents. To see distant thunder more clearly, you will need to filter out the VLF stuff. In the picture below you can see the effect of post process high pass filter:

vertical air currents (downdrafts)

when I say VLF I am broadly speaking of frequencies below 0.2 Hz