The seismicity of any region depends partly on the frequency, and partly on the intensity, of the earthquakes that occur within it. If earthquakes of all intensities are included in making such estimates, the weight to be given to the intensity must at present be to a great extent arbitrary. If, however, the determination is confined to earthquakes of the highest degrees of intensity, the results, though incomplete as representatives of the actual seismicities of the various regions considered, may yet give with some approach to accuracy their relative order of magnitude. The object of this brief paper is to provide such estimates for the various regions of the world and for the provinces of Italy that are shaken by destructive earthquakes.