The 300-mile ribbon of Mexican Pacific coastline that stretches from Manzanillo to Acapulco has long been considered one of the world's beautiful places, home to a sprinkling of fishing hamlets and resorts. Yet beneath the indigo waves and silky white beaches lies a jagged fault line that could be one of the deadliest in the Western Hemisphere. It was this fault that erupted under the Pacific last week, causing the earthquake that measured 7.8 on the Richter scale,* rocked coastal towns and brought disaster to Mexico City.
To scientists, the great quake and its aftershocks were not surprising. Karen McNally, a...