Earlier today a major earthquake estimated to have a magnitude of 7.3 struck near the Solomon Islands. At this stage reports are that 15 people have died as a result of the quake and resulting tsunami.
With the devastating 2004 Boxing Day tsunami still very much fresh in peoples’ minds, the entire Australian Eastern seaboard was put on alert with the BOM issuing a tsunami warning for Queensland, NSW and Tasmania. There was a rise in the sea level noted in some areas but nothing dangerous. Of course, the tsunami warning was not well handled by the media and the impression was at one stage of imminent waves of destruction. The SMH noted that such a warning is:
..the first stage of a three-step system towards evacuations – should be better explained to the public to prevent panic, a scientist says.
Today’s warning was the first from the Australian Tsunami Warning System, established after the 2004 Boxing Day tsunami, the University of Queensland’s Dr Dion Weatherley says.
Dr Weatherley, a research fellow at the university’s Earth Systems Science Computational Centre, also works with Geoscience Australia, helping them to monitor earthquakes.
He said Australia’s tsunami warning system has three stages, beginning with a “tsunami warning” like that issued this morning, followed by a “tsunami alert”, then a “tsunami alarm”.
Prior to 2004, the last tsunami warning was issued in 2001. Back in early 2005, I put together a history of tsunamis and Australia when I was blogging elsewhere. Forgive me as I plagiarise myself a little.
Tsunamis can and have hit Australia. In 1868 an earthquake off the coast of South America triggered a tsunami that was noticed in Sydney and Newcastle Harbours with boats stranded as the waters receded and/or damaged as the waters came. In more recent times, a tsunami was recorded in 1977 on the Western Australian coast and another in 1994. Both tsunamis were the result of earthquakes in the Java trench off Indonesia. Fortunately in both instances the tsunamis were not destructive. If you dig deeper into the past there is evidence of mega-tsunamis on both coasts of Australian (though these may been caused by a meteorite impact in the ocean rather than earthquakes).
The two areas with the highest risk are the North West and East (especially around Sydney) Coasts of Australia (including Tasmania). The NW coast is obviously in a region that can be affected by quakes in Indonesia. The East coast not only has quakes all around the Pacific to watch out for but New Zealand as well. From what I can gather, the southern part of Australia doesn’t seem a high risk area. I’m not sure why as I am no geologist but I suspect the type of earthquakes and ocean topography aren’t conducive to tsunamis. It seems that the majority of earthquake caused tsunamis have historically occurred on the west and east coasts. Although there is evidence that the Gulf St Vincent was the site of a tsunami after a meteorite impact quite a few years ago.
It was reported that many on the beaches seem unconcerned with the tsunami warning. Given the warning level, it was probably the right thing to do. But people shouldn’t get to complacent regarding the threat of tsunamis to Australia. They may be rare but not unknown.