A pair of big earthquakes, one a magnitude 6.9 and the other 6.1, struck off the coast of Japan today, prompting officials to issue tsunami advisories for a region still reeling from disaster.

No major waves were reported, but the tremors rattled plenty of nerves and prompted evacuations in seven cities rebuilding from the devastating tsunami one year ago, according to broadcaster NHK.

The first temblor struck after 6 p.m. Wednesday local time, 146 miles south of Kushiro, on the northernmost island of Hokkaido. The shallow quake immediately triggered tsunami advisories along a coastline that includes Iwate and Aomori Prefectures.

Hours later Tokyo shuddered from the rippling effects of a 6.1 quake that NHK reported was off the coast of Chiba. The second quake did not trigger a tsunami warning.

Iwate was among the three prefectures hardest hit, by a magnitude 9.0 quake that triggered a catastrophic tsunami last March.

The waves killed nearly 20,000 people and led to 3 meltdowns at the Fukushima Dai-ichi Power Plant.

There have been no immediate reports of damages at local power plants after this most recent quake. No injuries have been reported, so far.