In one apocalyptic moment on the afternoon of March 11, 2011, the Great Tōhoku Earthquake sent a giant tsunami wave sweeping over the city of Sendai, a peaceful metropolis of one million people in Northern Japan. The waves swept away vehicles, causing buildings to collapse and severing roads and highways. Debris swamped the city’s airport. The extent of the damage surprised even the most sophisticated of observers. To date, it has been difficult to nearly impossible to measure tsunamis or model defenses against it.