my crank pulley why does this keep happining?

[svxin]

ok this is the second crank pulley that i have some how destroyed. this one was on for about 100 miles its off my 94 i had this happen before but this time it went through the timming belt cover. i oraderd a new one piece pully for motorsport wharehouse i hope it holds up. why does this happen has anyone else had this happen to them. ill try and post a pic to show you what i mean. both times the pully seperated its self from the dampining material. is something wrong with my svx or does this happen a lot i really run this car hard maybe thats what is wrong.