Apparently [giant]* tsunamis are so rare in the Indian Ocean—once every 700 years—that there is no warning system in place. When the USGS detected the quake, they scrambled to send a warning, but couldn’t reach anyone in the area:
“We tried to do what we could,” McCreery said. “We don’t have contacts in our address book for anybody in that part of the world.”
Within moments of detecting the 9-magnitude quake, McCreery and his staff were on the phone to Australia, then to U.S. Naval officials, various U.S. embassies and finally the U.S. State Department.
Even with a warning system in place, it would have caused massive devastation, but there would have been time for many—maybe even most of the people who died (at least from the immediate deluge) to reach higher ground and safety.
Reportedly efforts are underway to set up a network.
*Update: I was recently looking back over this post & noticed the claim at the beginning, that tsunamis only hit every 700 years in the Indian ocean, and immediately thought, “this doesn’t make any sense!” I mean, Indonesia is kind of a hotbed of tectonic activity. Krakatoa, anyone?
The CNET article is still up, but didn’t offer any clarification. The exact quote was that “such catastrophes only happen there about once every 700 years.” But some quick searching turned up some clearer information: Tsunamis of this massive size are rare in the Indian ocean, not tsunamis in general. Here’s a 2008 Nature article on geological evidence for Indian Ocean megatsunamis over the past 2500 years, with previous events in the 1300s and 800s.