Look at this amazing almost real-time computer simulation! It shows how the tsunami was expected to cross the Pacific from Chile to New Zealand, before reaching Australia.
This real-time forecast by the Pacific Tsunami Warning Center shows residents of Hawaii, New Zealand and other islands that the time is short before a surprising freak wave strikes.
As described in the Youtube video:
This animation shows simulated tsunami wave propagation for 30 hours followed by an “energy map” showing the maximum open-ocean wave heights over that period and the forecasted tsunami runup heights on the coastlines.