Make 8 circle movieclips and use actionscript to tween them. It isn't clear to me what the pulsating effect needs to be, but you should be able to tween them individually, simultaneously, and/or sequencially as needed.
Thanks, ned, for quick response. guess that’s the way to go. I want the circles to spread like when you throw a stone into water: continuously moving outwards … (att. the earthquake map with the – not moving – circles)