A research group has estimated that tsunami waves generated by Monday's devastating earthquake in Japan started to reach the country's coast within roughly one minute of the quake.

The group included Professor Imamura Fumihiko of Tohoku University's International Research Institute of Disaster Science.

It used the quake's source fault data from the Geospatial Information Authority of Japan and the US Geological Survey to run a simulation on how the tsunami spread.

The group estimates that the first batch of waves reached the city of Suzu within about one minute of the quake and the city of Nanao within two minutes. They are on the Noto Peninsula, which juts out into the Sea of Japan.

It also says tsunami are also believed to have started to hit Toyama City, near the peninsula, within some five minutes of the quake.

The simulation also suggests that tsunami spread to northern and western Japan, with more continuing to hit the peninsula for many hours.

Imamura says tsunami triggered off the country's Sea of Japan coast are susceptible to seabed terrain due to shallow waters. He adds that tsunami that surged toward coastal areas after Monday's quake are believed to have ricocheted off the seabed topography.

Imamura says people should immediately evacuate from coastal areas in the event of large tremors as seismic activity remains active in the Noto region.