On the Perceptibility of Earthquakes

A method is presented to derive a first order approximation of the number of people likely to feel any earthquake, assuming a uniform population distribution. The “most perceptible” earthquake is a function of the frequency of earthquake occurrence (there are more small earthquakes) and effect (large ones will be felt by more people). The method is demonstrated taking the UK as a test case. The trade-off between the two trends seems to produce a peak value of about 4.5 ML for the earthquake that the typical inhabitant of the UK is most likely to have felt. It is also found that a UK citizen who lives for 70 years has a roughly 42% chance of experiencing a British earthquake at some point in their life. In practice, of course, the issue is complicated both by irregular population distribution and to some extent regional irregularities in the magnitude-frequency distribution for the UK. The method is easily adaptable to other countries; its relevance is chiefly in the generation of statistics of interest to the public at large, thus aiding public understanding of science.