Wow, that belt is shredded into little pieces. If only it could have lasted a couple more days. Nuts! Is the alternator rotor frozen? Have you checked that all the pulleys other than the alternator rotate freely without excessive noise or wobble? If yes, this demonstrates that a properly working clutch pulley reduces stress on the belt by allowing the alternator rotor to spin freely during engine deacceleration. If the alternator rotor is not frozen, and this happened to the belt because the clutch pulley failed, then I'm wondering if the belt tensioner was damaged by excessive belt vibrations over a long period of time. Check for excessive belt bouncing after the alternator is repaired.