Tsunami Felt at Sydney Olympic Park

The eruption of the volcano Hunga Tonga-Hunga Ha'apai created a tsunami that spread across the Pacific Ocean, even reaching into the quiet mangrove forests at Sydney Olympic Park.

Sydney Olympic Park has been recording tides moving in and out of the Powells Creek mangroves since 2001. This automated tidal gauge continuously records data on water levels and captures information on what influences them: atmospheric pressure, a big ferry travelling nearby or heavy stormwater flows. It is also a reliable tool to detect relative rise in sea level in the local area. The gauge was installed to inform Sydney Olympic Park of tidal dynamics to guide short and long-term management of estuarine wetlands like mangroves and other assets nearby.

On the 15 January, the gauge clearly recorded the impulses of the tsunami that occurred across the Pacific Ocean from the eruption near Tonga. The tsunami was triggered at 3:10pm AEDT, and waves first arrived in Sydney just after 6pm. The image below shows the readings taken at the Powells Creek gauge from 13-18 January 2022.

The red line shows tsunami waves arriving in the mangroves on the evening of 15 January and they continued for two days before petering out after 18 January. The blue line represents the difference between the predicted tidal height and the actual recording made by the gauge.
In just three hours, the impulse had travelled to Sydney Olympic Park's mangrove forests across approximately 3,500 kilometre of sea. This is comparable to twice the speed of the fastest passenger aircraft flight!

Mangroves play an important part in protecting our shoreline and if the waves had been bigger, their impact would have been partially dispersed through the forest, protecting us from harm.

Watch the tide flow into the Badu Mangroves