What was used in these circumstances was a "swap transaction," which exchanges the yen and the euro for the dollar for a certain period of time (Chart 11). Since this was dollar funding using the yen and the euro as collateral, or vice versa, it was relatively safer than uncollateralized funds transactions.
In a sense this liquidity is a consequence of the central banks’ monetary operations, but it is important to underline that the central banks have merely made this liquidity available against collateral; they have not in any way “pumped” money into the system in excess of what is demanded by banks.