FIGURE 8.23 A massive earthquake (Mw 9.1) off the Indonesian island of Sumatra sent a tsunami racing across the Indian Ocean and Bay of Bengal on December 26, 2004. A. Unsuspecting foreign tourists, who at first walked on the sand after the water receded, now rush toward shore as the first of six tsunami roll toward Hat Rai Lay Beach near Krabi in southern Thailand. (AFP/Getty Images Inc.) B. Tsunami survivors walk among the debris from this earthquake- triggered event.