US has subprime problem, but why USD strengthen?

Just wondering, US has housing subprime problem for the last 2 or 3 months, but why would the USD going strong againts EUR and GBP. Anybody can explain to me please.....

Because the USD is still very much a safe haven currency. When investment firms started losing money on mortgage investments, they have to dump them and then purchase USD because it's a safe haven.

Take that chaos and panic and sprinkle a dash of carry trade unwinding, and what you have is USD gaining strength.

but I don't know... to me it still seems weak. I don't see how it could return to respectable levels anytime soon. I know because I make my money in USD... once a point of pride, now a point of shame

Short term bonds. This is a dumb move because the dollar will come under massive selling pressure toward the end of this year.

I think, Yen is strenthening against dolar which is drying the liquidity and dolar is returning home.