Scientists are learning how to predict tsunami risk
Last Nov. 16, at 8:43 p.m., a magnitude-7.5 earthquake struck deep beneath the ocean near Alaska's Little Sitkin Island, far out in the Aleutian Islands. Within 25 minutes, National Oceanographic and Atmospheric Administration (NOAA) scientists issued a tsunami warning for U.S. Pacific coastal areas. Forty minutes later, a pressure sensor on the seafloor hundreds of kilometers south of Alaska detected the tsunami's vanguard pulses. Data from that instrument—one of six in a network activated just the previous month—indicated that the wave was only 2 centimeters tall there. Simulations previously run on computers suggested that such a wave wouldn't be a danger to Hawaii or other distant shores, and NOAA canceled its tsunami warning less than 90 minutes after the quake occurred.