The aim of the ECGS workshop 2012 was bringing scientists from all around the world working on all aspects of earthquake source physics and scaling around one table to discuss and look for solutions to the problems still encountered. A range of research groups has made significant developments since the last major conference purely dedicated to radiated energy and the physics of faulting held in 2005 in Portland, Maine, USA (American Geophysical Union Chapman conference). The major aim of this 2012 ECGS workshop is therefore to consolidate conflicting views and decipher the reasons for these discrepancies as well as to foster collaborations of scientists working on all scales of the problem.