In Miki, Japan, a six-story wooden model condominium was shaken by the equivalent of a 7.5 magnitude earthquake. The test was said to be the largest simulated earthquake ever attempted with a wooden structure. The full-scale building sat on a metal shake table that rocked it violently back and forth. The table, designed to hold up to 2.5 million pounds, reproduced forces based on those recorded during the 1994 earthquake in Northridge, California. But, it was scaled up by 180 percent to simulate an earthquake so violent it would only occur an average of once every 2,500 years. Part of the "Science Nation" series.