Earthquakes and their attendant phenomena rank among the most terrifying natural disasters faced by mankind. Out of a clear blue sky—or worse, a jet-black one—comes shaking strong enough to hurl furniture across the room, human bodies out of bed, and entire houses off their foundations. Individuals who experience the full brunt of the planet’s strongest convulsions often later describe the single thought that echoed in their minds during the tumult: I am going to die. When the dust settles, the immediate aftermath of an earthquake in an urbanized society can be profound. Phone service and water supplies can be disrupted for days, fires can erupt, and even a small number of overpass collapses can impede rescue operations and snarl traffic for months. On an increasingly urban planet, millions of people have positioned themselves directly in harm’s way. Global settlement patterns have in all too many cases resulted in enormous concentrations of humanity in some of the planet’s most dangerous earthquake zones. On the holiday Sunday morning of December 26, 2004, citizens and tourists in countries around the rim of the Indian Ocean were at work and at play when an enormous M9 (magnitude 9.0) earthquake suddenly unleashed a torrent of water several times larger than the volume of the Great Salt Lake. The world then watched with horror as events unfolded: a death toll that climbed toward 300,000 that was accompanied by unimaginable, and seemingly insurmountable, devastation to hundreds of towns and cities. For scientists involved with earthquake hazards research in that part of the world, the images were doubly wrenching: the hazard from large global earthquakes has been recognized for decades. Located mostly offshore, the 2004 Sumatra quake unleashed its destructive fury primarily in the sea. The next great earthquake to affect Asia might well be inland, perhaps along the Himalayan front or in central China.