A great offshore earthquake, like the one that killed hundreds of thousands when it struck off Indonesia’s Sumatra coast in December 2004, would seem to offer a small measure of solace to survivors: The offshore tectonic fault that caused the temblor should require many centuries to recharge. Now, it appears such optimism is unwarranted. Three speakers here at the fall meeting of the American Geophysical Union earlier this month warned that the Indian Ocean coast of northern Sumatra could suffer another tsunami disaster in as few as 60 years.