Indonesia tsunami

Anak Krakatau, whose partial collapse is blamed for triggering Saturday's tsunami that killed at least 430 people, remains active — spewing ash over a large area around the Sunda Strait.

The tsunami that battered coastlines along the Sunda Strait over the weekend follows a similar wave that pounded the island of Sulawesi in September, killing an estimated 2,100.

Warning systems failed to alert residents of danger when volcanic activity triggered a tsunami on Saturday. Hundreds died, and more than 11,000 people have been displaced on Java and Sumatra islands.

Communications are still down to some of the hardest-hit regions on the island of Sulawesi. "This is already a tragedy, but it could get much worse," says one aid official.

On Dec. 26, 2004, a massive earthquake in the ocean east of the Indonesian island of Sumatra triggered waves that killed 230,000 people in 11 countries.