What effect did the Boxing Day tsunami have on Western Australia?
The Boxing Day tsunami was clearly recorded on tide gauges along the entire Western Australian coast, arriving at different times at different sites. See the tsunami arrival times page. While the deep water travel speed of roughly 1000 km/h would be expected to cause 1-2 hours lag from north to south, the lag is counteracted by the width of the continental shelf, which causes dramatic slowing of the wave. Along the majority of stations, a signal of 0.5-2.0 m has been identified, producing dramatic oscillations of the water level, which persisted for 4-5 days, gradually reducing in scale. The size of the signal appears to be determined by continental shelf width, coast shape and gauge location. Onslow and Geraldton have a narrow shelf, and experienced a large signal. Busselton tide gauge is located near to the apex of a northwest facing embayment and experienced a larger signal. The gauge at Exmouth experienced a relatively small signal, but is strongly sheltered within the shallow wate
