A dam in the northeast Fukushima prefecture of Japan broke and homes were washed away, Kyodo news reported, following the biggest earthquake in the nation's history.

The Sankei Shimbun newspaper reported that the Fujinuma irrigation dam in Sukagawa city, Fukushima, had collapsed, with homes washed away and people missing.

The dam was a 57-foot-tall and 436-foot-long embankment-type dam located on a tributary of the Abukuma River, reports indicate. 

The number of homes destroyed as a result of the dam rupture is unknown. Casualty numbers also are unknown.

The 8.9-magnitude earthquake - the seventh biggest ever recorded - generated a monster wall of water that pulverized the northeastern city of Sendai, where police reportedly said that 200-300 bodies had been found on the coast.

At least 310 people were killed in the massive earthquake and following tsunamis, police and press reports said.

The government declared an atomic power emergency as officials worked to secure nuclear facilities in the affected regions, media reports indicate.

Hours after the Japan quake struck, TV images showed orange balls of flame rolling up into the night sky as fires raged around a petrochemical complex in Sendai.

A massive fire also engulfed an oil refinery in Iichihara near Tokyo.

For more hydropower news and information, click here