My first earthquake

Well, my first earthquake that I’ve noticed. And I was very excited indeed. On Saturday 17 February at 2.31 in the afternoon there was a magnitude 4.4 earthquake with its epicentre c. 20 km NNE of Swansea in south Wales, so about 140 km from us. The tremors were felt across much of the UK. This is pretty small beer in the scale of things (my brother in New Zealand probably wouldn’t even call this an earthquake …), but it was the most powerful earthquake in the generally not-very-seismically-active UK for ten years. As it was relatively shallow (7.4 km) it was well felt throughout large parts of Wales and England. And I was very excited to feel it.

I was sitting at my desk in my study upstairs. The floorboards are old and a little loose, and I felt them wobble, as if a heavy lorry was passing by (except we live up a rough track too narrow for a lorry) or if someone was standing behind me jiggling up and down and making the floorboards wallow a little. I called down to Chap to ask if he had felt it, but he hadn’t – he was standing on the concrete floor, so maybe that made the difference – fewer points of contact on a harder, less flexible surface.

The response on the EMSC website ‘did you feel it?’ survey.

I added my observations to both the British Geological Survey (BGS) and United States Geological Survey (USGS)‘s ‘Did you feel it?’ questionnaires, as well as the EMSC website. The responses to these citizen science surveys help seismologists in their studies. Interestingly, the BGS has the magnitude at 4.6 and the USGS at 4.2. I’m going with with the EMSC and BBC’s reported 4.4.

I’ve probably experienced earthquakes before (I’ve lived and worked in several seismically active earthquake zones) but this is the first I’ve noticed.