In March 1964, an earthquake measuring 8.5 on the Richter scale hit western Alaska. These violent shifts generated a tsunami that moved down the west coast of America and hit the low-lying northern shores of California.
Hardest hit was the port of Crescent City, where four successive waves, the highest reaching about six metres, roared across the harbour and into the city. Huge physical damage was caused. But just 11 people lost their lives.
There were good early warning systems, allowing the authorities to evacuate many of the most vulnerable people. The Americans had the capacity to mount immediate rescue efforts and to protect those made homeless from hunger and disease. So, while the 1964 tsunami was horrible and traumatic, it was, compared to the effects of the Asian tsunami 40 years later, a minor disaster.
What the comparison suggests is that there is, in a sense, no such thing as a natural disaster any more. The "natural" bit is, of course, still true. Earthquakes, tsunami, hurricanes, tornadoes, volcanoes, landslides and floods are all inherent in the nature of our planet, though their frequency and effect is certainly influenced by human actions such as deforestation and the use of fossil fuels. But a disaster is a human event, its scale and severity increasingly determined by the way we organise our world. It is shaped, not by natural forces alone, but by poverty, inequality and bad governance. If we are as shocked as we seem to be by the deaths of perhaps a quarter of a million people in the Asian tsunami, we need to respond, not only to the immediate plight of those worst affected, but to the injustices that turn a physical event into a human disaster.
Blaming nature is more comforting than engaging with the reality that a disaster such as the one that has just unfolded is the result of human choices. We still refer to earthquakes as "acts of God" as if to underline their lack of connection to politics and economics.
In a statement launching his newspapers' entirely admirable South East Asia Relief Fund, Sir Anthony O'Reilly was oddly insistent on the entirely natural cause of the disaster: "This natural calamity was simply that, natural; our universe is subject to forces outside our control." Yet the obvious truth is that the effects of events such as these are largely within our control. We can't stop earthquakes and tidal waves but we can massively reduce the vulnerability of people to the dangers they pose.
People in poor countries are hugely more vulnerable to the risk of dying in a "natural disaster" than those in rich countries. Between 1974 and 2003 there were 6,367 natural disasters, not counting epidemics. They resulted in the reported deaths of slightly more than two million individuals, with 5.1 billion people affected in some way, and 182 million people made homeless. The vast majority of these people were in poorer countries. Asia alone suffered 75 per cent of the deaths from natural disasters. And this isn't for the reason most people might think: the dumb luck of geography that makes some places more prone to extreme physical events than others.
A UN Development Programme study in 2000 found that populations in wealthy countries represent 15 per cent of those exposed to natural disasters, but only 1.8 per cent of those who are killed. Iran, the US and Japan, for example, are all prone to earthquakes. Between 1980 and 2000, an average of 1,074 people in Iran were killed each year in earthquakes, for every million inhabitants exposed to the risk of an earthquake. By comparison, 0.97 were killed each year per million exposed in the US.
In other words, the relative vulnerability of Iranians to earthquakes is over a thousand times greater that the relative vulnerability of Americans and over a hundred times greater than the relative vulnerability of the Japanese.
The same is true for other natural hazards. In 2002, an average of 555 people died per disaster in very poor countries, compared to 133 in less poor countries and 18 in rich countries.
There's no great mystery about why this should be so. Social factors (high levels of poverty force growing numbers of poor people to live in harm's way - on flood plains, in earthquake-prone zones and on unstable hillsides), political and economic factors (failure to consider natural disasters in the location and characteristics of economic activity), and environmental factors (inappropriate land use on steep slopes, deforestation, erosion, dangerous location of settlements) and organisational factors (early warning systems and effective rescue operations) all matter far more in the creation of disasters that natural factors do.
What this means is that generosity that has us all digging into our pockets is welcome but wildly inadequate. Future disasters can be prevented right now, and we can all do something about it. As well as making donations, we can demand that our Government reverses its shameful decision to abandon its promise to meet the UN target for development aid. Otherwise, our charity will continue to be a drop in a cruel ocean of injustice.