Well, first of all.
Australian interest rates going down subsequently as a result of a slowing economy, namely falls in commodity prices. Thus future commodity contracts having a lower value and a revised economic growth estimate.
1% decrease made investors leave the australian bond market and some investors withdrew from countries with a high CAD e.g. australia thus withdrawing from australian equity.
Japanese investors sold australian dollars in order to unyield their exchange rate speculation, this is manifest through australia losing about 50% to the JPY. Also investors are going into JPY because it is seen as the safest currencies as a result of their consistent trade surpluses.
Furthermore with declining commodity and oil prices we have seen the mining/commodity economies i.e. brasil, canada and Australia have their currencies slip against most currencies as a result of revised estimates for global economic growth and thus the price of commodities.
With the USA going down, we also have seen china revise it's economic growth from 10.8% to 9.4% thus decreased demand for commodities.
Also australia has slipped relative to the USA because the risk of investment is a lot lower due to the transperency and liquidity of usa bonds.
One would think that declining AD and a faltering financial sector in the USA that prompts huge monetary printing response would devalue the USD however don't forget the fact that the USD is seen as a reserve currency and easily transformed into another, namely the JPY and this can be seen with the USD's consequent decline against the JPY by about 10%. Until the USA stops producing technology it's economy won't go into depression.
There is also the fact that currencies are like sandbags and that they dont spread out. This can be seen with a lot of currencies 're-adjusting' I dare say, and moving all over the place against each other.
Don't forget that the AUD is near its trough as most investors are trying to salvage their portfolios rather than make informed decisions.
I think i/r differential, investor confidence in australia's CAD and commodities are the most prevalent factors in the depreciation of the australian dollar.