Among the book s various tables is one listing the number of wars in which deaths exceeded a given figure. For example, he found that between the years of 1820 and 1929 there were 24 conflicts in the world, each of which resulted in more than 30,000 deaths. His terminology is suggestive, for it hints at a link with another form of global catastrophe, earthquakes. The parallels go deeper than mere words, however. At its extremes, the line reflected common sense, showing that there have been relatively few wars producing huge death-tolls.
Skirmishes resulting in several thousand deaths are far more common.
But, remarkably, conflicts between these two extremes also lie on the same straight line. The law was first identified in 1956 by American geophysicist Charles Richter and his colleague, Beno Gutenberg. There is no more chance of being able to identify the key stimulus unleashing historical upheaval than there is of being able to say which piece of falling rice will trigger a huge avalanche of grain Like conflicts, devastating quakes are mercifully rare, while minor tremors occur all the time. But, as Richardson also discovered with conflicts, quakes of intermediate magnitude also lie along the same straight line. According to new research the answer lies, surprisingly, in the behaviour of heaps of grain.