In general, the Ishimoto-Iida relation between the maximum trace amplitude a and the number of earthquakes n(a)

n(a) = k a−m

holds good for earthquakes observed at an observation where k and m are constant [Ishimoto and Iida, 1939].

On the other hand, Suzuki [1953, 1955] says that the parameter m in this relation is connected with b in the Gutenberg-Richter relation log N = a−bM where a and b are constant [Gutenberg and Richter, 1942, 1956]. Suzuki derived a relation of b = m − 1 from the theoretical basis, under an assumption that the decay factor of seismic waves was constant regardless of earthquake magnitude.