The b variability with the Moho depth and the link between aftershocks and afterslip

We have investigated the dependence of the Gutenberg-Richter b parameter on the Moho depth h in many areas of the world. We have found that b increases with h. This observation has be interpreted in terms of aftershocks occurrence. Indeed aftershocks are generated by the stress released by the  afterslip occurred i n the ductile zone beneath the brittle one. The depth of the Moho has been, here, used as an indicator of the coupling between the brittle and the ductile zones. As h increases the coupling increases generating more aftershocks. These are characterized by an higher b value leading to our observation.