Researchers of the tsunami which killed 186 people in the Samoas and Tonga say the world must learn to respond more quickly to such events.
Teams from the California based Earthquake Engineering Research Institute and the state's Emergency Management Agency have been studying the Samoan response, impact and recovery from the disaster.
Kate Long, from the California Emergency Management Agency, says a lot of Samoans did the right thing by quickly moving to higher ground, but many didn't.
"Many people didn't realise that in a tsunami that comes from an earthquake very close, you're never going to get an official warning before the wave arrives. The earthquake is too close; it takes too long for the scientists to read their instruments. So many people waited for the water to recede, but that's the second sign of a tsunami. The first sign is the earth shaking."
Kate Long says the Agency's advice is if an earthquake lasts longer than 20 seconds or is so hard you cannot stand, then go to higher ground immediately.