By Dorothy Davis
Japan's northeast was rattled again by another major aftershock Monday just as the battered nation marked the one-month anniversary of the devastating earthquake and tsunami that killed at least 25,000 and set off the current nuclear crisis.
Monday’s aftershock is the second in less than a week to hit the already ravaged nation. On April 7, a magnitude 7.1 earthquake spared the Fukushima complex from further damage but did result in the temporary loss of power and the leakage of water from spent fuel pools at the Onagawa nuclear station located in the Miyagi Prefecture.
The April 11 earthquake occurred at 5:16 p.m. local time and was measured by the Japan Meteorological Agency as a 7.1 magnitude earthquake, while the US Geological Survey measured the quake at a 6.6 magnitude.
The epicenter was in-land at Eastern Honshu, approximately 50 miles away from the Fukushima nuclear power complex. An alert was issued for a 3-foot tsunami, but the warning was later lifted.
For comprehensive coverage of the Japanese nuclear power disaster and efforts under way to resolve it, visit PennEnergy’s Japan Earthquake and Nuclear Emergency 2011 special section.
The International Atomic Energy Agency reports the Nuclear and Industrial Safety Agency (NISA) confirmed no changes have been observed on the readings at the on-site radiation monitoring posts; and power remains available at the Fukushima, Onagawa and Tokai nuclear power stations after Monday’s event.
Workers at the Fukushima nuclear complex were evacuated to the seismic evacuation shelter as off-site power was interrupted then restored. TEPCO said water injections resumed 50 minutes after the earthquake at Units 1, 2 and 3.
Meanwhile, Japan has widened the evacuation area around the Fukushima nuclear complex urging residents of five more communities to evacuate in the next few weeks because of high radiation levels.