You may want to read this:http://timesonline.typepad.com/dons_life/2011/10/has-another-pompeii-wall-collapsed.html
The short answer is 'no'.
By chance I am on the site of Pompeii for the weekend. It is now swarming with more journalists than tourists, and all (it seems) with a determination to hype another collapse, another Pompeian disaster. That is to say, they are here with a determined misunderstanding of what has just happened -- or with a drive to use any damage to the site as a stick with which to beat Berlusconi