There are a number of earthquake and tsunami early warning systems in operation across the world. Here is a link to one in California: http://www.seismicwarning.com/
Before the recent tsunami in Japan, their warning systems only managed to alert the authorities 15 minutes before it hit…
Of course earthquake predictions can be improved as at the moment they can only give hours or minutes warning, but this is enough to get people starting to evacuate high-risk areas, so it is pretty incredible!
The only contribution I can make as a computer scientist is perhaps from the side of better computational modelling of the problem — designing systems, algorithms and techniques to more accurately predict and measure earthquakes.