Didn't have time to expand before: Richter measures the energy produced at the centre, below the ground. Mercalli describes the effects at the epicentre, above it, and out to the very fringes of the quake. A deep quake with a high Richter number could have the same Mercalli number as a smaller quake nearer the surface. While most of our British quakes don't deserve mention in the company of folk from the western States, we do occasionally have bigger ones in the South. Being intraplate and not at plate margins, the effects spread further before dying out. The Colchester quake caused the large tower at the Houses of Parliament to shake so much that workmen had to rush downstairs, and a small tsunami was seen crossing the Thames. In the same way, the 1382 Canterbury quake was felt in London. Because they are rare, there have been few buildings to be affected in the past, though there have been a significant number of collapsed churches (eg St. Michael's at Glastonbury Tor). In 1884, old cottages survived, distorted but upright, because they did not have foundations in the earth. Since then, many buildings have been built with, understandably, little regard for earthquake proofing. Anyway, the Colchester quake was followed by a wave of sales of work and other fund raising, and I would have thought that such an event would have stirred someone to song. Music Hall songs, at least.