The Cosmo oil refinery in Chiba prefecture outside Tokyo has exploded, sending flames dozens of metres into the air with firefighters unable to contain the inferno.

There are reports of more than 40 major fires across Japan following the 8.9-magnitude offshore quake.

Five nuclear power plants and several oil refineries shut down automatically after the quake.

Officials say no radiation leaks have been reported.

Hokuriku Electric Co said all three reactors at its Onagawa nuclear plant in northern Japan were shut down, while JX Nippon Oil and Energy Corp, Japan's top refiner, halted operations at three refineries in Sendai, Kashima and Negishi.

Electric Power Development also halted operations of its Isogo thermal power plant in Yokohama, and electronics giant Sony Corp, one of the country's biggest exporters, shut six factories.

The Miyagi prefecture and surrounding areas include major manufacturing and industrial zones, with many chemical, petrochemical and electronics plants.

Television showed black smoke pouring out of an industrial area in Yokohama's Isogo area.

A fire was also reported at JFE Holdings Incorporated's steel plant in Chiba. JFE is the world's fifth-largest steelmaker.

Two people were reported killed by a collapsing ceiling at a Honda factory in Tochigi prefecture but no other details were immediately available.

Several airports, including Tokyo's Narita, were closed and rail services were halted.

The car park at Tokyo Disneyland was drenched with water-logged segments from the ground following the quake.

It was earlier reported that a tsunami might have caused the inundation but police said the phenomenon was due to liquefaction of soil caused by the intense shaking of the tremor.

There were 69,000 people at Disneyland and the adjacent Tokyo Disney Sea, but there were no injuries or property damage reported.

abc.net.au

My prayers are with them.