Arran Tremor measures 1.3
at 11:52am on the 12th of August there was an earthquake on Arran! It only measured 1.3 on the Richter scale, but that’s big enough to be felt by some people if they are in the right place. Earthquake on Arran are not unusual, in 1999 a magnitude 4 earthquake was recorded in a similar location just south of Arran.
ArranWeather.com has a page detailing the most recent earthquake in the UK, you can see that here