MELBOURNE, Australia — All over the world, people have responded generously to the devastating earthquake that struck Haiti. In just three days, more than a million Americans had donated $10 by sending text messages from their cell phones. People with very little themselves, like Maria Pacheco, an unemployed single mother from Chicago, donated food and clothes.

Others did whatever they could — from pedicures to washing cars — to raise money. On current indications, the amount Americans will give to relief efforts in Haiti could surpass the $1.9 billion they gave to assist victims of the 2004 Asian tsunami, which until now has stood as a record for donations to a disaster outside the United States. Given that the U.S. is undergoing economic hard times, the size of the response has surprised many.

Haiti's proximity, plus the fact that close to a million Haitians live in the U.S., goes some way toward explaining why Americans have responded so generously. But the response has been worldwide.