That was one of the reasons why I wanted to update starling
I used the explanations from starling as3 forum : How to create a Shock wave effect with displacementMapFilter like this? - Starling Forum
Demo here : ShockwaveDemo
Source code here GitHub - MatseFR/starling-demos
edit : it requires starling 2.7, which is now available (thanks Josh !) from the OpenFL GitHub GitHub - openfl/starling: The "Cross-Platform Game Engine", a popular Stage3D framework