Japan Marks 7 Years Since Earthquake, Tsunami and Nuclear Disasters Prime Minister Shinzo Abe commemorated the 18,500 people who died when a magnitude 9.0 tremor struck the Pacific Ocean on March 11, 2011. The quake triggered a tsunami, causing even greater damage. The tsunami knocked out power at the Fukushima Daiichi power plant, sparking the worst nuclear disaster since Chernobyl in 1986. While Shinzo Abe said construction is still in progress... more than 70,000 people remain displaced.