The scientists from New Zealand's National Institute of Water and Atmospheric Research and GNS Science said they found up to three powerful waves had been caused by a magnitude 8.0 undersea earthquake.
The massive waves that struck Samoa, American Samoa and Tonga totally destroyed traditional wooden buildings along the coast, many of them single storey structures.
|Entire villages were destroyed as the powerful waves smashed into the islands [EPA]
Stefan Reese, a risk engineer with the institute, said reinforced concrete buildings however sustained only minor damage.
"In some areas there was virtually nothing left" after the waves reached up to 700 metres inland, he told The Associated Press, adding that wide reefs saved some villages by helping to reduce the waves' height to about three metres.
The scientists said the Samoa tsunami consisted of two to three significant waves, citing eyewitness accounts that the second wave was larger.
Their findings showed that the delay between the earthquake and the arrival of the first wave was about 10 minutes in Samoa and 20 minutes in American Samoa.
Tsunami waves can travel at speeds of 800-1,000 kph.
The deadliest quake of recent years was the December 26, 2004 event off the coast of Sumatra that spawned a region-wide tsunami killing more than 240,000 people across Asia – including 170,000 in Indonesia alone.