Temporal Variations in the Parameters of the Unified Scaling Law for Earthquakes in the Eastern Part of Honshu Island (Japan)

摘要

The fundamental property of multiple destruction is the power law of the distribution of the number of events N(E) by energy log_(10)N(E) = a + blog_(10)E, (1) known in seismology as one of the Guttenberg-Richter relations. Usually, coefficient b is equal to b = 2/3 , and the relation is valid for averaging over a large spatiotemporal volume within finite limits of energy E variation from E_(min) to E_(max). The Guttenberg-Richter recurrence law is usually formulated as a ratio, which establishes a relation between the annual mean number of earthquakes N(M) and their magnitude M in a fixed spatiotemporal volume: log_(10)N(M) = a + b(5-M), M_- ≤ M ≤ M~-. (2) Coefficient a characterizes the level of seismic activity in the entire spatiotemporal volume, and coefficient b is the ratio of the number of earthquakes in the neighboring ranges of magnitudes. Researchers usually consider the magnitude of M_S or M_W type, whose logarithm is proportional to the earthquake source area. Under such a formulation, coefficient b in the recurrence law is close to unity.