I am a new player and as i am taking this spell for my magus and being new i read it as NO to the weapons bonus. It is a reaction from stomping your foot or hitting the ground with a weapon. A +5 almighty hammer of tripping won't make the ripple any bigger. And its the ripple doing the tripping. The caster level and or Int/wis/cha replacement makes up for not using the weapons emhancement bonus i think.
I could be wrong butfrom a new players view point thats how i read it