On April 7, 2011, at 11:32 p.m local time, a strong aftershock which registered at 7.1-magnitude on the Richter Scale struck Northern Japan again which is same epicenter of the devastating 9.0-magnitude earthquake on March 11. At first it was reported magnitude 7.4 but later downgraded to 7.1.
A tsunami warning of up to 6 feet was issued immediately and people along the coastline were told to evacuate. The tsumani warning was lifted after 90 minutes.
According to reports, the tremor also caused power shutdown in several areas in the Northeast and may have further damaged the Fukushima plant. Workers also evacuated the plant until the danger of tsunami caused by this latest shock is past.
The powerful April 7 earthquake killed 2 and injured a hundred people, according to latest news reports.
Here's a Youtube video of the April 7, 2011 Japan Earthquake:
April 7, 2011 Japan Earthquake | Video courtesy of Youtube