Spatial variations of seismic b-values distribution in China

Seismic frequency-magnitude relationship has been investigated in China, based on the earthquake data in the range of M3.0 to M7.0 during the years 1986-2008, to study the potential of variations of b-values with the depth. According to the results, there is a systematic decrease in b value with increasing depth of earthquakes. At the shallow depth conditions, with more heterogeneous material properties and lower lithosphere stress prevail, rupture initiation is more likely to stop before accumulating into large earthquakes, producing relatively smaller earthquakes and consequently higher b-values. On the contrary, the larger earthquakes are more likely to happen at a greater depth. © (2011) Trans Tech Publications.