A magnitude 7.3 earthquake struck off the east coast of Honshu, Japan, at 11:36 p.m. (local time) yesterday, resulting in significant ground shaking near the epicenter, much structural damage, at least four deaths, and a power outage affecting more than 2 million households, including some 700,000 in Tokyo. (According to Japanese utility Tepco, power was restored to all households by 2:52 a.m. on Thursday.)