HIGH FLYERS THINK TANK

Extreme Natural Hazards

University of Melbourne, Tuesday 30 October 2007

Opening address

Professor Kurt Lambeck, President, Australian Academy of Science

Natural hazards are something that humans have had to live with throughout time. They reflect the natural processes that have shaped the planet, and which, in fact, have made life possible and endurable.

We cannot prevent the build up of stress within the planet, nor can we prevent the Earth's deep interior heat from seeking an escape to the surface.

What has changed is that with instant communications, there is a much greater awareness of the consequences. Compare the near instantaneous transmission of information at the time of the 2004 Boxing Day tsunami when someone in the tsunami-affected area was warned by an anxious phone call from a father in Sweden, with the months it took for the extent of the Krakatoa eruption to be realised in Europe. Compare the graphic real-time images beamed across the world with the written descriptions of the Krakatoa event that reached much of Europe long after the casualties were buried.

What has also changed is that populations have increased such that when the Earth system is put under stress the consequences can be so much greater. Pressures on land use often lead to infrastructure decisions that would normally be considered outlandish. Placing a nuclear reactor on a fault line or in the shadow of an active volcano does not in itself constitute a natural hazard but it has the potential to turn a minor natural hazard into a major disaster.

Equally, infrastructural changes can also reduce the consequences of natural hazards. Engineering solutions, in particular, can result in much reduced damage and casualties in earthquake zones. And this occurs in most seismically active developed countries, whereas events of similar magnitude in the developing world often result in far greater damage and casualty rates. Consider the 2003 Bam–Iran earthquake, curiously also on Boxing Day. This was a magnitude 6.6 event, similar to the San Simeon earthquake a year earlier in California. Both occurred in seismically active regions, at similar shallow depths (~8 km), and were strike-slip movements.

But despite their similarities, their human consequences were vastly different. The California quake left two people dead and 40 buildings damaged. The Bam earthquake is believed to have killed at least 35,000 people and flattened 90 per cent of the buildings in the city. The crucial difference was the implementation of building construction codes, not the intensity of the tremor. That churches and temples sometimes survive these events where dwellings don't is a reflection on building construction methods rather than on the whims of gods.

The 1989 Newcastle earthquake, of a rather modest 5.6 magnitude, teaches a similar lesson, causing considerably more damage than a similar-sized event is likely to produce in Tokyo or New Zealand.

The recent fires in California provide a different example: one where anomalous meteorological conditions were turned into a major disaster through the careless or malevolent actions of a few.

Another difference from the past is that we now have a much greater, if still imperfect, understanding of the processes at work. We no longer need 'The Spirit of the Earth' Maradika Puhu to stir the Earth into action. And even if we cannot yet predict where the next hazard will strike, what science can assess is which regions are particularly susceptible to natural hazards and, in some cases, provide early warning; always with the proviso that someone had the foresight to put observation networks in place, before Alatala decides that Putu inserts his thumb into the bowl.

Natural hazards include not only the events emanating from inside the Earth. They also include disturbances in the atmosphere and hydrological events. These have also been part of the human experience but they are likely to have been influenced by human activity. Changing patterns of land use have led to major slope instability in mountainous areas of Asia and South America and to increased silting-up of river deltas and to degradation of groundwater systems. More ominous is our effect on climate, globally and regionally, which has the potential to create major disruptions with global consequences.

So, there are enough reasons why this year's High Flyers Think Tank addresses extreme natural hazards.

Past Think Tanks have resulted in reports to government that have contributed to policy development. I see no reason why this should not be the case with this Think Tank. It is topical. Australia is not immune from natural hazards. It may not be possible to prevent all natural hazards from occurring but one can be prepared and one can mitigate the consequences. It is an issue where good science, engineering, public policy and sociology should come together along with new innovative ideas. This is what the Think Tank is about: to bring together a group of researchers from different backgrounds to identify gaps in knowledge and to examine novel applications of existing science and technology.

I look forward to using the final report of this Think Tank in debate about proofing Australia against the consequences of extreme natural hazards.