Scotty, To think interest rate rise will cause "every" house owners to sell causing 80% fall in value is childish....
Any of these must be met to create a massive 80% crash.
-unemployment more than 35% ( you'll be sacked first ) -china stop buying our commodity "Totally" causing chain reaction financial disaster ( you'll be sacked too ) -extreme extreme political tension between china / australia like rumour of war, causing "All" chinese investor to flee (in fact Abbott is begging for FTA) -massive major earthquake/calamities like end of days scenario ( the company you work for is flatten - you'll be sacked ) -world war 3 ( you'll be in bunker & sacked )
It's gonna be a long melancholy wait before any of these to occur.