Compared with disasters like the Asian tsunami and Hurricane Katrina, those in China and Myanmar have generated just a trickle of aid. As of Friday, Americans had given about $12.1 million to charities for Myanmar, according to the Center on Philanthropy at Indiana University. The group said on Monday that it was too soon to count contributions to China.

wikipedia defines it as:

Compassion fatigue is a term that refers to a gradual lessening of compassion over time. Compassion fatigue may occur when, due to the media saturation of stories and images of people who are suffering (e.g. images of starving children in Africa, or extended war reporting) people develop a resistance to these images or stories. As the impact of these messages lessens, their willingness to give to causes reduces.

see also

• Cynicism
• Bystander effect
• Diffusion of responsibility