Tsunami event summary - Wednesday, 15 July 2009

Details of earthquake:

Magnitude 7.9 occurred near the New Zealand south coast at 7:22pm EST.

Australia's warning response:

7.22pm Earthquake detected off the south-west tip of New Zealand.
7.30pm Geoscience Australia locates the earthquake and activates the tsunami warning centre.
7.46pm The bureau issues a Tsunami Watch 24 minutes after the earthquake.
7.50pm Deep-ocean buoy in the southern Tasman Sea confirms the existence of a tsunami.
8.05pm Tsunami Warning (Land Threat) issued for Lord Howe Island.
8.17pm Tsunami Warning (Marine Threat) issued for the mainland, Tasmania and Norfolk Island.
10.30pm Tsunami waves of about 30cm are recorded at Port Kembla.

Impacts on Australia

Small tsunami were observed (approximately 3 hours after the earthquake) at several Australian sea-level gauges, including Port Kembla, NSW, and no damage was reported. The largest tsunami was at Southport in southern Tasmania which recorded a 55-centimetre sea level difference above the expected tidal level.

Sea level changes at Port Kembla, NSW on 15 July 2009 as a result of a tsunami

Figure 1: Sea level at Port Kembla, NSW, during the tsunami on 15 July 2009.