Giving for the tsunami was literally off the charts. There may be an issue of donor fatigue, it's too early to tell, but it looks like giving for the Pakistan earthquake is more typical of the historical response by U.S. donors to international emergencies.
It's just shocking how far off the charts 9/11, the tsunami and the hurricanes are.
The tsunami was a really good example of altruistic giving. (Most Americans) didn't know anyone there or had a strong connection; 9/11 had an element of patriotism. For this hurricane, the vast miles of destruction, plus the raw numbers affected, is one of the things driving that.