Japanese researchers said they found a new way to define tsunamis: Observe magnetic fields generated by tsunami-induced movements of seawater.

The researchers said such observations make it easier to determine the direction, size and arrival time of a tsunami, Jiji Press reported Thursday.

The team said it successfully detected magnetic fields generated as tsunami spread after a massive earthquake off Chile in February 2010. Using underwater, high-precision electromagnetometers, the team said it detected magnetic fields near Tahiti, nearly 4,350 miles away.

The findings were published in the British journal Scientific Reports.