2007 Kent earthquake earthquake in 1950. The strongest recorded British earthquake is the 1931 Dogger Bank earthquake, which measured 6.1 on the Richter scale. Ten months later, the earthquake's strength was surpassed by that of the 2008 Lincolnshire earthquake, which was 5.2 in magnitude. Less than two years later, on 3 March 2009 at 14.35 UTC, Folkestone was shaken by a smaller magnitude 3.0 quake, located in the same area. 2007 Kent earthquake The 2007 Kent earthquake registered 4.3 on the Richter scale and struck south east Kent, South East England on 28 April 2007 at 07:18:12 UTC (08:18:12 local time), at a
Moment magnitude scale band. To simplify this calculation, he noted that the lowest frequency parts of the spectrum can often be used to estimate the rest of the spectrum. The lowest frequency asymptote of a seismic spectrum is characterized by the seismic moment, . Using an approximate relation between radiated energy and seismic moment (which assumes stress drop is complete and ignores fracture energy), (where E is in Joules and is in Nformula_4m), Kanamori approximated by The formula above made it much easier to estimate the energy-based magnitude , but it changed the fundamental nature of the scale into a moment magnitude scale.