the currencty movements are the liquid amounts that flow from those that are thought of a weak to those that are stronger, the yen and dollar are seen as fairly safe havens, before this crisis the money men would borrow in japan and invest elsewhere for higher return now that some of these countries where higher returns were offered are seen as vunerable hence flo back to dollar and yen, it could have included sterling if our wonderful leader had known what he was doing over the last 10 years.