The video: On Thursday, a strong underground earthquake struck in the Pacific Ocean near the north central coast of Japan, 60 miles east of Sendai. At a magnitude of 7.1, the aftershock was the most severe since March 11, when a 9.0-magnitude quake devastated large swaths of the country. This latest earthquake violently shook buildings in Sendai and rattled skyscrapers as far away as Tokyo. (See a video from Sendai below.) Some injuries have been reported, but no deaths. Anticipating another lethal flood, the Japan Meteorological Agency quickly issued a tsunami warning, but later called it off when no dangerous waves appeared. At the crippled Fukushima power plant, workers were evacuated, but no change in radiation levels was reported. The most visible effect of the quake may have come in the U.S. stock market, where Japanese futures dropped precipitously.
The reaction: Don't be alarmed, says Don Blakeman, a geophysicist in the U.S. National Earthquake Information Center, as quoted by Bloomberg Businessweek. This was "tremendously smaller than the main shock [which] caused about 80 times more ground movement." For investors, "the concern is further disruptions to the economic base of Japan," says Martin Schultz, a portfolio manager quoted by Bloomberg. The March 11 earthquake had global financial repercussions because it affected "the supply chain of some of the companies that are leaders in the technology industry" — and another disaster could just worsen the problem. See the video from Sendai: