I was in the church in Chicago many years ago. The glass in the EXIT signs started to rattle. I thought it might be a bus that went past on the main street.
When I got home later I turn on TV news and find the Sandwich Fault SW of Chicago had about a 4.5 magnitude quake. Those shock waves travel further thru sedimentary rock than igneous. ;)
OMG! Did people there seemed surprised -- or is it a somewhat common occurrence?
The Sandwich Fault is relatively inactive but it can unleash a moderate quake now and then.
Actually, there was no one else in the church at the time. Now they keep the churches locked up when there are no services because of thieves and arsonists. ;)