Heterogeneities along the 2009 L'Aquila normal fault inferred by the b‐value distribution

In this study we map the distribution of the b‐value of the Gutenberg‐Richter law—as well as complementary seismicity parameters—along the fault responsible for the 2009 MW6.1 L'Aquila earthquake. We perform the calculations for two independent aftershock sub‐catalogs, before and after a stable magnitude of completeness is reached. We find a substantial spatial variability of the b‐values, which range from 0.6 to 1.3 over the fault plane. The comparison between the spatial distribution of the b‐values and the main‐shock slip pattern shows that the largest slip occurs in normal‐to‐high b‐values portion of the fault plane, while low b‐value is observed close to the main‐shock nucleation. No substantial differences are found in the b‐value computed before and after the main‐shock struck in the small region of the fault plane populated by foreshocks.